Apparatus and method

ABSTRACT

[Object] To adaptively adjust a symbol interval or a subcarrier interval in accordance with a communication environment. [Solution] There is provided an apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that transmission is performed from the communication unit to a terminal by narrowing at least one of a symbol interval of a complex symbol sequence in a time direction and a subcarrier interval of the complex symbol sequence in a frequency direction, the complex symbol sequence being converted from a bit sequence, the symbol interval and the subcarrier interval being set on a basis of a predetermined condition.

TECHNICAL FIELD

The present disclosure relates to an apparatus and a method.

BACKGROUND ART

In the conventional modulation schemes applied in standards such as LTE(Long Term Evolution)/LTE-A (Advanced), the symbol intervals of symbolsmodulated in accordance with PSK/QAM or the like are set in accordancewith the Nyquist criterion such that temporally continuous symbols donot interfere with each other (i.e., no inter-symbol interferenceoccurs). This allows a reception apparatus side to demodulate and decodereception signals with no special signal processing but attendantprocessing such as orthogonal frequency-division multiplexing (OFDM) ormultiple-input and multiple-output (MIMO). However, from the perspectiveof frequency use efficiency, it is difficult to narrow the symbolintervals of the modulated symbols beyond conditions of the symbolintervals, so that the upper limit is defined in accordance with thegiven frequency bandwidth, the number of MIMO antennas, and the like. Itis considered to extend the frequency band of the communication systemfrom the existing microwave band to the submillimeter-wave band, themillimeter-wave band, or the like, which is higher frequency. However,the limit will be reached some day because of limited frequency bandresources. In addition, MIMO also has a physical restriction as to theinstallation of antennas in an apparatus, so that this will also reachthe limit.

Under such circumstances, the technology referred to asfaster-than-Nyquist (FTN) has attracted attention. For example, PatentLiterature 1 discloses FTN. FTN is a modulation scheme and atransmission scheme which narrow the symbol intervals of modulatedsymbols beyond the above-described conditions of the symbol intervals toattempt to improve frequency use efficiency. Although inter-symbolinterference occurs between temporally continuous symbols in the processof modulation, and a reception apparatus side requires special signalprocessing to receive FTN signals, such a configuration makes itpossible to improve frequency use efficiency in accordance with the wayto narrow symbol intervals.

CITATION LIST Patent Literature

Patent Literature 1: US 2006/0013332A

DISCLOSURE OF INVENTION Technical Problem

Meanwhile, in the case where FTN is applied, as described above,inter-symbol interference occurs between temporally continuous symbols.Accordingly, signal processing is necessary to allow a receptionapparatus side to receive FTN signals, and the signal processing can bea factor that increases the load on the reception apparatus side.

Accordingly, the present disclosure proposes an apparatus and a methodcapable of adaptively adjusting a symbol interval or a subcarrierinterval in accordance with a communication environment.

Solution to Problem

According to the present disclosure, there is provided an apparatusincluding: a communication unit configured to perform radiocommunication; and a control unit configured to perform control suchthat transmission is performed from the communication unit to a terminalby narrowing at least one of a symbol interval of a complex symbolsequence in a time direction and a subcarrier interval of the complexsymbol sequence in a frequency direction, the complex symbol sequencebeing converted from a bit sequence, the symbol interval and thesubcarrier interval being set on a basis of a predetermined condition.

In addition, according to the present disclosure, there is provided amethod including: performing radio communication; and performing, by aprocessor, control such that radio transmission is performed from thecommunication unit to a terminal by narrowing at least one of a symbolinterval of a complex symbol sequence in a time direction and asubcarrier interval of the complex symbol sequence in a frequencydirection, the complex symbol sequence being converted from a bitsequence, the symbol interval and the subcarrier interval being set on abasis of a predetermined condition.

Advantageous Effects of Invention

According to the present disclosure, as described above, it is possibleto provide an apparatus and a method capable of adaptively adjusting asymbol interval or a subcarrier interval in accordance with acommunication environment.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is an explanatory diagram for describing an example oftransmission processing in a case where FTN is employed.

FIG. 1B is an explanatory diagram for describing an example of awaveform shaping filer output of a Nyquist rate signal.

FIG. 1C is an explanatory diagram for describing an example of awaveform shaping filter output of a Faster-Than-Nyquist signal.

FIG. 2 is an explanatory diagram for describing an example of receptionprocessing in the case where FTN is employed.

FIG. 3 is an explanatory diagram illustrating an example of a schematicconfiguration of a system according to an embodiment of the presentdisclosure.

FIG. 4 is a block diagram illustrating an example of a configuration ofa base station according to the embodiment.

FIG. 5 is a block diagram illustrating an example of a configuration ofa terminal apparatus according to the embodiment.

FIG. 6 is an explanatory diagram for describing an example of aconfiguration of a time resource in a case where FTN is supported.

FIG. 7 is an explanatory diagram for describing an example of processingin a transmission apparatus that supports FTN.

FIG. 8 is an explanatory diagram for describing an example of theprocessing in the transmission apparatus that supports FTN.

FIG. 9 is an explanatory diagram for describing an example of theprocessing in the transmission apparatus that supports FTN.

FIG. 10 is an explanatory diagram for describing an example of theprocessing in the transmission apparatus that supports FTN.

FIG. 11 is a diagram illustrating an example of a relationship betweenfrequency of a channel, a level of inter-symbol interference, and acompression coefficient.

FIG. 12 is a flowchart illustrating an example of processing of settinga compression coefficient in accordance with frequency of a channel.

FIG. 13 is a diagram illustrating another example of the relationshipbetween frequency of a channel, a level of inter-symbol interference,and a compression coefficient.

FIG. 14 is a flowchart illustrating an example of processing of settinga compression coefficient in accordance with whether a target CC is aPCC or an SCC.

FIG. 15 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for a downlink.

FIG. 16 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink.

FIG. 17 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for an uplink.

FIG. 18 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for the uplink.

FIG. 19 is a diagram illustrating an example of a frequency channel usedfor communication between a base station and a terminal apparatus in acommunication system in which carrier aggregation is employed.

FIG. 20 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for a downlink ina communication system in which carrier aggregation is employed.

FIG. 21 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 22 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 23 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 24 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 25 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 26 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for the downlink.

FIG. 27 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for the uplink.

FIG. 28 is an explanatory diagram for describing an example ofsynchronization of boundaries in a subframe unit at the time of thecarrier aggregation.

FIG. 29 is an explanatory diagram for describing an example ofsynchronization of boundaries in a subframe unit at the time of thecarrier aggregation.

FIG. 30 is a diagram illustrating an example of a case where boundariesof radio frames are synchronized between different component carriers.

FIG. 31 is a flowchart illustrating an example of a determination flowfor performing cross-carrier scheduling.

FIG. 32 is a flowchart illustrating an example of a determination flowfor performing cross-carrier scheduling.

FIG. 33 is a flowchart illustrating an example of determination forperforming dual-connectivity in a case where a plurality of componentcarriers are used.

FIG. 34 is a flowchart illustrating an example of determination forperforming the dual-connectivity in a case where it is determined that avalue of FTN parameter is included.

FIG. 35 is an explanatory diagram for describing an example of aconfiguration of a transmission apparatus according to an embodiment inwhich multi-carrier modulation is set as a base.

FIG. 36 is an explanatory diagram for describing an example of aconfiguration of a transmission apparatus according to an embodiment inwhich multi-carrier modulation is set as a base.

FIG. 37 is an explanatory diagram for describing sub-carrier disposition(conventional sub-carrier disposition) in a case where compression in afrequency direction is not performed.

FIG. 38 is an explanatory diagram for describing sub-carrier dispositionin a case where compression in the frequency direction is performedaccording to the embodiment.

FIG. 39 is an explanatory diagram for describing an example of a casewhere the length of a subframe or the length of TTI is constantregardless of compression in a time direction.

FIG. 40 is an explanatory diagram for describing an example of a casewhere the length of a subframe or the length of TTI is constantregardless of compression in a time direction.

FIG. 41 is a flowchart illustrating an example of a determination flowfor changing a configuration of a resource element with respect to achange in a value of a compression coefficient.

FIG. 42 is an explanatory diagram for describing an example in which thenumber of symbols per subframe or the number of symbols per TTI isconstant regardless of compression in the time direction.

FIG. 43 is an explanatory diagram for describing an example in which thenumber of symbols per subframe or the number of symbols per TTI isconstant regardless of compression in the time direction and the lengthof the subframe.

FIG. 44 is an explanatory diagram for describing an example of a casewhere a bandwidth of a resource block is maintained constantlyregardless of presence or absence (magnitude) of compression in thefrequency direction.

FIG. 45 is an explanatory diagram for describing an example of a casewhere a bandwidth of a resource block is constant regardless ofcompression in the frequency direction.

FIG. 46 is an explanatory diagram for describing an example of resourcecompression at a boundary of a time resource allocation unit and aboundary of a frequency resource allocation unit.

FIG. 47 is an explanatory diagram for describing an example of resourcecompression at a boundary of a time resource allocation unit and aboundary of a frequency resource allocation unit.

FIG. 48 is an explanatory diagram for describing an example of resourcecompression at a boundary of a time resource allocation unit and aboundary of a frequency resource allocation unit.

FIG. 49 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 50 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 51 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 52 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Note that the description will be made in the following order.

1. FTN 2. Technical Problem 3. Schematic Configuration of System 4.Configuration of Each Apparatus 4.1. Configuration of Base Station 4.2.Configuration of Terminal Apparatus 5. Technical Features 6.Modifications 6.1. Modification 1: Example of Control of Prefix

6.2. Modification 2: Example of Control according to Moving Speed ofApparatus

6.3. Modification 3: Extension to Multi-carrier Modulation 6.4.Modification 4: Introduction of Compression in Time Direction andCompression in Frequency Direction 7. Application Examples

7.1. Application Example regarding Base Station7.2. Application Example regarding Terminal Apparatus

8. Conclusion 1. FTN

First, with reference to FIGS. 1 and 2, the overview of FTN will bedescribed. In the conventional modulation schemes applied in standardssuch as LTE/LTE-A, the symbol intervals of symbols modulated inaccordance with PSK/QAM or the like are set in accordance with theNyquist criterion such that temporally continuous symbols do notinterfere with each other (i.e., no inter-symbol interference occurs).This allows a reception apparatus side to demodulate and decodereception signals without performing special signal processing (exceptfor attendant processing such as OFDM or MIMO. However, from theperspective of frequency use efficiency, it is difficult to narrow thesymbol intervals of the modulated symbols beyond conditions of thesymbol intervals, so that the upper limit is defined in accordance withthe given frequency bandwidth, the number of MIMO antennas, and thelike. It is considered to extend the frequency band of the communicationsystem from the existing microwave band to the submillimeter-wave band,the millimeter-wave band, or the like, which is higher frequency.However, the limit will be reached some day because of limited frequencyband resources. In addition, MIMO also has a physical restriction as tothe installation of antennas in an apparatus, so that this will alsoreach the limit.

Under such circumstances, the technology referred to asfaster-than-Nyquist (FTN) has attracted attention. FTN is a modulationscheme/transmission scheme which narrows the symbol intervals ofmodulated symbols beyond the above-described conditions of the symbolintervals to attempt to improve frequency use efficiency. Althoughinter-symbol interference occurs between temporally continuous symbols,and a reception apparatus side requires special signal processing toreceive FTN signals, such a configuration makes it possible to improvefrequency use efficiency in accordance with the way to narrow symbolintervals. Note that FTN has a considerable advantage that it ispossible to improve frequency use efficiency without extending afrequency band or increasing an antenna.

For example, FIG. 1A is an explanatory diagram for describing an exampleof transmission processing in the case where FTN is employed. Note that,as illustrated in FIG. 1A, even in the case where FTN is employed, theprocessing up to adding an error correction code to and performingPSK/QAM modulation on a bit sequence is similar to the conventionaltransmission processing applied in the standards such as LTE/LTE-A. Inaddition, in the case where FTN is employed, as illustrated in FIG. 1A,FTN mapping processing is performed on the bit sequence on which PSK/QAMmodulation has been performed. In the FTN mapping processing,over-sampling processing is performed on the bit sequence, and then awaveform shaping filter adjusts the symbol intervals beyond a Nyquistcriterion. Note that, the bit sequence on which FTN mapping processinghas been performed is subjected to digital/analog conversion, radiofrequency processing and the like, and sent to an antenna.

Comparison between waveform shaping filter outputs of a Nyquist ratesignal and a Faster-Than-Nyquist signal is illustrated in each of FIGS.1B and 1C. A conventional Nyquist rate signal is designed so thatinter-symbol interference (ISI) does not occur since temporallycontinuous symbols are subjected to zero cross at a sample timing. Onthe other hand, in FTN, an effective symbol rate is increased bynarrowing a symbol interval with a variable (herein referred to as atime compression coefficient t). In the example of FIG. 1C, a case oft=0.7 is illustrated. Inter-symbol interference is contained in an FTNsignal itself since temporally continuous symbols are not subjected tozero cross even at a sample timing unlike a Nyquist rate signal.

Herein, from FIGS. 1B and 1C, it is necessary to be careful that asymbol length is the same between a Nyquist rate signal and an FTNsignal. That is, in Faster-Than-Nyquist, the symbol length is notshortened (a signal bandwidth is not enlarged) to increase a speed.

In addition, FIG. 2 is an explanatory diagram for describing an exampleof reception processing in the case where FTN is employed. A receptionsignal received at an antenna is subjected to radio frequencyprocessing, analog/digital conversion and the like, and then FTNde-mapping processing is performed thereon. In the FTN de-mappingprocessing, a matched filter corresponding to a waveform shaping filteron a transmission side, downsampling, whitening processing of residualnoise, and the like are performed on a reception signal converted into adigital signal. Note that channel equalization processing is performedon the digital signal (bit sequence) on which FTN de-mapping processinghas been performed, and then the processing from de-mapping to errorcorrection decoding is performed for an attempt to decode a transmissionbit sequence similarly to the conventional reception processing appliedin the standards such as LTE/LTE-A.

Note that, in the following description, it will be assumed that thesimple term “FTN processing” in transmission processing represents FTNmapping processing. Similarly, it will be assumed that the simple term“FTN processing” in reception processing represents FTN de-mappingprocessing. In addition, the transmission processing and the receptionprocessing described above with reference to FIGS. 1A to 2 are merelyexamples, but are not necessarily limited to the contents. For example,various kinds of processing accompanying the application of MIMO,various kinds of processing for multiplexing, and the like may beincluded.

With reference to FIGS. 1A to 2, the above describes the overview ofFTN.

2. Technical Problem

Next, a technical problem according to an embodiment of the presentdisclosure will be described.

As described above, FTN is capable of improving frequency use efficiencywithout extending a band or increasing the number of antennas.Meanwhile, in the case where FTN is applied, as described above,inter-symbol interference occurs between temporally continuous symbolsin the process of modulation. Therefore, signal processing (i.e., FTNde-mapping processing) for receiving FTN signals is necessary on areception apparatus side. Therefore, it can be assumed that simplyemploying FTN alone excessively increases the load on a receptionapparatus in FTN de-mapping processing, and deteriorates thecommunication quality of the overall system, for example, depending onthe state or condition of communication, the performance of thereception apparatus, or the like (which will be collectively referred toas “communication environment” below in some cases).

Accordingly, the present disclosure proposes an example of a mechanismcapable of adaptively adjusting a symbol interval in a more favorablemanner in accordance with a communication environment in the case whereFTN is applied.

<<3. Schematic Configuration of System>>

First, the schematic configuration of a system 1 according to anembodiment of the present disclosure will be described with reference toFIG. 3. FIG. 3 is an explanatory diagram illustrating an example of theschematic configuration of the system 1 according to an embodiment ofthe present disclosure. With reference to FIG. 3, the system 1 includesa base station 100 and a terminal apparatus 200. Here, the terminalapparatus 200 is also referred to as user. The user can also be referredto as user equipment (UE). Here, the UE may be a UE defined in LTE orLTE-A, or may generally refer to a communication apparatus.

(1) Base Station 100

The base station 100 is a base station of a cellular system (or mobilecommunication system). The base station 100 performs radio communicationwith a terminal apparatus (e.g., terminal apparatus 200) positioned in acell 10 of the base station 100. For example, the base station 100transmits a downlink signal to a terminal apparatus and receives anuplink signal from the terminal apparatus.

(2) Terminal Apparatus 200

The terminal apparatus 200 can perform communication in a cellularsystem (or mobile communication system). The terminal apparatus 200performs radio communication with a base station (e.g., base station100) of the cellular system. For example, the terminal apparatus 200receives a downlink signal from a base station and transmits an uplinksignal to the base station.

(3) Adjustment of Symbol Intervals

Especially in an embodiment of the present disclosure, when transmittingdata to the terminal apparatus 200, the base station 100 adjusts thesymbol intervals between the symbols of the data. More specifically, thebase station 100 performs FTN mapping processing on a bit sequence oftransmission target data on a downlink to adjust the symbol intervalsbetween the symbols of the data beyond a Nyquist criterion (i.e., makean adjustment such that the symbol intervals are narrower). In thiscase, for example, the terminal apparatus 200 performs demodulation anddecoding processing including FTN de-mapping processing on a receptionsignal from the base station 100 to attempt to decode the datatransmitted from the base station 100.

In addition, in an amplifier link, the symbol intervals between symbolsbased on FTN processing may be adjusted. In this case, the terminalapparatus 200 performs FTN mapping processing on a bit sequence oftransmission target data to adjust the symbol intervals between thesymbols of the data. In addition, the base station 100 performsdemodulation and decoding processing including FTN de-mapping processingon a reception signal from the terminal apparatus 200 to attempt todecode the data transmitted from the terminal apparatus 200.

The above describes the schematic configuration of the system 1according to an embodiment of the present disclosure with reference toFIG. 3.

4. Configuration of Each Apparatus

Next, with reference to FIGS. 4 and 5, the configurations of the basestation 100 and the terminal apparatus 200 according to an embodiment ofthe present disclosure will be described.

<4.1. Configuration of Base Station>

First, with reference to FIG. 4, an example of the configuration of thebase station 100 according to an embodiment of the present disclosurewill be described. FIG. 4 is a block diagram illustrating an example ofthe configuration of the base station 100 according to an embodiment ofthe present disclosure. As illustrated in FIG. 4, the base station 100includes an antenna unit 110, a radio communication unit 120, a networkcommunication unit 130, a storage unit 140, and a processing unit 150.

(1) Antenna Unit 110

The antenna unit 110 emits a signal output by the radio communicationunit 120 to the space as a radio wave. In addition, the antenna unit 110converts a radio wave in the space into a signal and outputs the signalto the radio communication unit 120.

(2) Radio Communication Unit 120

The radio communication unit 120 transmits and receives signals. Forexample, the radio communication unit 120 transmits a downlink signal toa terminal apparatus and receives an uplink signal from the terminalapparatus.

(3) Network Communication Unit 130

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toanother node and receives information from the other node. For example,the other node includes another base station and a core network node.

(4) Storage Unit 140

The storage unit 140 temporarily or permanently stores programs andvarious kinds of data for the operation of the base station 100.

(5) Processing Unit 150

The processing unit 150 provides the various functions of the basestation 100. For example, the processing unit 150 may include acommunication processing unit 151 and a notification unit 153. Note thatthe processing unit 150 can further include other components in additionto these components. That is, the processing unit 150 can also performoperations other than the operations of these components.

The communication processing unit 151 and the notification unit 153 willbe described in detail below. The above describes an example of theconfiguration of the base station 100 according to an embodiment of thepresent disclosure with reference to FIG. 4.

<4.2. Configuration of Terminal Apparatus>

Next, an example of the configuration of the terminal apparatus 200according to an embodiment of the present disclosure will be describedwith reference to FIG. 5. FIG. 5 is a block diagram illustrating anexample of the configuration of the terminal apparatus 200 according toan embodiment of the present disclosure. As illustrated in FIG. 5, theterminal apparatus 200 includes an antenna unit 210, a radiocommunication unit 220, a storage unit 230, and a processing unit 240.

(1) Antenna Unit 210

The antenna unit 210 emits a signal output by the radio communicationunit 220 to the space as a radio wave. In addition, the antenna unit 210converts a radio wave in the space into a signal and outputs the signalto the radio communication unit 220.

(2) Radio Communication Unit 220

The radio communication unit 220 transmits and receives signals. Forexample, the radio communication unit 220 receives a downlink signalfrom a base station and transmits an uplink signal to the base station.

(3) Storage Unit 230

The storage unit 230 temporarily or permanently stores programs andvarious kinds of data for the operation of the terminal apparatus 200.

(4) Processing Unit 240

The processing unit 240 provides the various functions of the terminalapparatus 200. For example, the processing unit 240 includes aninformation acquisition unit 241 and a communication processing unit243. Note that the processing unit 240 can further include othercomponents in addition to these components. That is, the processing unit240 can also perform operations other than the operations of thesecomponents.

The information acquisition unit 241 and the communication processingunit 243 will be described in detail below. The above describes anexample of the configuration of the terminal apparatus 200 according toan embodiment of the present disclosure with reference to FIG. 5.

5. Technical Features

Next, technical features according to an embodiment of the presentembodiment will be described with reference to FIGS. 6 to 23.

(1) Example of Time Resource Configuration

First, with reference to FIG. 6, an example of the configuration of atime resource in the case where FTN is supported will be described. FIG.6 is an explanatory diagram for describing an example of theconfiguration of a time resource in the case where FTN is supported.

In the example illustrated in FIG. 6, a time resource is divided intounits referred to as radio frames along a time-axis direction. Inaddition, a radio frame is divided into a predetermined number ofsubframes along the time-axis direction. Note that, in the exampleillustrated in FIG. 6, a radio frame includes ten subframes. Note that atime resource is allocated to a user in units of subframes.

In addition, a subframe is divided into a predetermined number of unitsreferred to as symbol blocks further along the time-axis direction. Forexample, in the example illustrated in FIG. 6, a subframe includesfourteen symbol blocks. A symbol block has a sequence portion includingsymbols for sending data, and a CP portion in which a part of thesequence is copied. In addition, as another example, a symbol block mayhave a sequence portion including symbols for sending data, and asequence portion (so-called pilot symbols) including known symbols. Notethat a CP or a pilot symbol can function, for example, as a guardinterval.

With reference to FIG. 6, the above describes an example of theconfiguration of a time resource in the case where FTN is supported.

(2) Example of Processing in Transmission Apparatus

Next, with reference to FIGS. 7 to 10, an example of processing in atransmission apparatus that supports FTN will be described. FIGS. 7 to10 are explanatory diagrams each for describing an example of theprocessing in the transmission apparatus that supports FTN. In theexamples illustrated in FIGS. 7 to 10, it is assumed that FTN signalsare transmitted to one or more users (i.e., the number N_(U) of users(or the number of reception apparatuses) ≥1). In addition, in theexamples illustrated in FIGS. 7 to 10, multi-antenna transmission isassumed (i.e., the number N_(AP) of transmission antenna ports (or thenumber of transmission antennas) ≥1). Note that the transmissionapparatus in the present description can correspond to both the basestation 100 and the terminal apparatus 200. That is, on a downlink, thebase station 100 corresponds to the transmission apparatus, and chieflythe communication processing unit 151 in the base station 100 executesprocessing described below. In addition, on an uplink, the terminalapparatus 200 corresponds to the transmission apparatus, and chiefly thecommunication processing unit 243 in the terminal apparatus 200 executesprocessing described below. In other words, the communication processingunit 151 or the communication processing unit 243 can function as anexample of the control unit of the present disclosure. Note that theterminal apparatus 200 corresponds to a reception apparatus on adownlink, and the base station 100 corresponds to a reception apparatuson an uplink.

Specifically, in the examples illustrated in FIGS. 7 and 8, for example,the respective bit sequences (e.g., transport blocks) of a user A, auser B, and a user C are processed. For each of these bit sequences,some processing (such as cyclic redundancy check (CRC) encoding, forwarderror correction (FEC) encoding, rate matching, andscrambling/interleaving, for example, as illustrated in FIG. 7) isperformed, and then modulation is performed. As illustrated in FIG. 8,layer mapping, power allocation, precoding, and SPC multiplexing arethen performed, and a bit sequence of each antenna element is output.Here, description will be made, assuming that the respective bitsequences corresponding to an antenna p1, an antenna p2, and an antennap3 are output.

As illustrated in FIG. 9, discrete Fourier transform (DFT)/fast Fouriertransform (FFT), resource element mapping, inverse discrete Fouriertransform (IDFT)/inverse fast Fourier transform (IFFT), cyclic prefix(CP) insertion, and the like are performed on the respective bitsequences corresponding to the antenna p1, the antenna p2, and theantenna p3, and a symbol sequence of each antenna element to which a CPhas been added is output. As illustrated in FIG. 10, as FTN processing,over-sampling and pulse shaping are then performed on the symbolsequence to which a CP has been added, and the output thereof isconverted from digital to analog and radio frequency (RF).

Note that the processing of the transmission apparatus described withreference to FIGS. 7 to 10 is merely an example, but is not necessarilylimited to the contents. For example, the transmission apparatus may bea transmission apparatus for which single antenna transmission isassumed. In this case, corresponding part of each processing describedabove may be replaced as appropriate.

With reference to FIGS. 7 to 10, the above describes an example ofprocessing in a transmission apparatus that supports FTN.

(3) Transmission Signal Processing

Next, an example of transmission signal processing in the case where FTNis employed will be described. Note that, in the present description, amulti-cell system such as a heterogeneous network (HetNet) or a smallcell enhancement (SCE) is assumed.

First, in the present description, it is assumed that an indexcorresponding to a subframe is omitted unless otherwise stated. Inaddition, in the case where the index of a transmission apparatus i andthe index of a reception apparatus u are respectively set as i and u,the indexes i and u may be indexes that represent the IDs of the cellsto which the corresponding apparatuses belong, or the IDs of the cellsthat are managed by the corresponding apparatuses.

Here, a bit sequence transmitted in a certain subframe t from thetransmission apparatus i to the reception apparatus u is set as b_(i,u).This bit sequence b_(i,u) may be a bit sequence included in onetransport block. In addition, description will be made in the presentdescription, using, as an example, the case where one bit sequence istransmitted from the transmission apparatus i to the reception apparatusu. However, a plurality of bit sequences may be transmitted from thetransmission apparatus i to the reception apparatus u, and the pluralityof bit sequences may be included in a plurality of transport blocks andtransmitted at that time.

First, processing such as encoding for CRC, FEC encoding (convolutionalcode, turbo code, LDPC code, or the like), rate matching for adjustingan encoding rate, bit scrambling, and bit interleaving is performed onthe transmission target bit sequence b_(i,u). Note that, in the casewhere each of these kinds of processing is used as a function, the bitsequences on which the respective kinds of processing have beenperformed are expressed as follows.

b _(CRC,i,u) =CRC _(ENC)(b _(i,u) ,u,i,t)

b _(FEC,i,u) =FEC _(ENC)(b _(CRC,i,u) ,u,i,t)

b _(RM,i,u) =RM(b _(FEC,i,u) ,u,i,t)

b _(SCC,i,u) =SCR(b _(RM,i,u) ,u,i,t)

b _(INT,i,u)=π(b _(SCR,i,u) ,u,i,t)  [Math. 1]

The bit sequence (e.g., bit sequence b_(INT,i,u)) on which theabove-described bit processing has been performed is mapped to a complexsymbol s (e.g., BPSK, QPSK, 8PSK, 16QAM, 64QAM, 256QAM, or the like),and further mapped to a spatial layer 1. Here, if the number of spatiallayers for the reception apparatus u is represented as N_(SLi,u), thetransmission signal to which the bit sequence b_(INT,i,u) has beenmapped can be expressed in the form of a vector as follows.

$\begin{matrix}{{s_{i,u} = \begin{bmatrix}s_{i,u,0} \\\vdots \\s_{i,u,{N_{{SL},i,\mu} - 1}}\end{bmatrix}}{s_{i,u,l} = \left\lbrack {s_{i,u,l,0}\mspace{14mu} \cdots \mspace{14mu} s_{i,u,l,{N - 1}}} \right\rbrack}} & \left\lbrack {{Math}.\mspace{14mu} 2} \right\rbrack\end{matrix}$

Note that, in the equation shown above, each element of a vectorS_(i,u,j) corresponds to the complex symbol s to which the bit sequenceb_(INT,i,u) is mapped.

Next, the respective kinds of processing of power allocation andprecoding are performed on the transmission signal that has been mappedto the spatial layer. Here, in the case where the number of antennaports (or the number of transmission antennas) in the transmissionapparatus i is represented as N_(AP,i), the transmission signal on whichpower allocation and precoding have been performed is shown as a vectorx_(i,u) below.

$\begin{matrix}{\begin{matrix}{x_{i,u} = {W_{i,u}P_{i,u}s_{i,u}}} \\{= \begin{bmatrix}x_{i,u,0,0} & \cdots & x_{i,u,{N_{{EL},{TTL}} - 1}} \\\vdots & \ddots & \vdots \\x_{i,u,{N_{AP} - 1},0} & \cdots & x_{i,u,{N_{AP} - 1},{N_{{EL},{TTL}} - 1}}\end{bmatrix}} \\{= \begin{bmatrix}x_{i,u,0} \\\vdots \\x_{i,u,{N_{AP} - 1}}\end{bmatrix}}\end{matrix}{x_{i,u,p} = \left\lbrack {x_{i,u,p,0}\mspace{14mu} \cdots \mspace{14mu} x_{i,u,p,{N_{{EL},{TTL}} - 1}}} \right\rbrack}{W_{i,u} = \begin{bmatrix}w_{i,u,0,0} & \cdots & w_{i,u,0,{N_{{SL},i,u} - 1}} \\\vdots & \ddots & \vdots \\w_{i,u,{N_{{AP},i} - 1},0} & \cdots & w_{i,u,{N_{{AP},i} - 1},{N_{{SL},i,u} - 1}}\end{bmatrix}}{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & \cdots & P_{i,u,0,{N_{{SL},i,u} - 1}} \\\vdots & \ddots & \vdots \\P_{i,u,{N_{{SL},i,u} - 1},0} & \cdots & P_{i,u,{N_{{SL},i,u} - 1},{N_{{SL},i,u} - 1}}\end{bmatrix}}} & \left\lbrack {{Math}.\mspace{14mu} 3} \right\rbrack\end{matrix}$

Note that, in the equation shown above, a matrix W_(i,u) is a precodingmatrix for the reception apparatus u. It is desirable that an element inthis matrix be a complex number or a real number. In addition, a matrixP_(i,u) is a power allocation coefficient matrix for transmitting asignal from the transmission apparatus i to the reception apparatus u.In this matrix, it is desirable that each element be a positive realnumber. Note that this matrix P_(i,u) may be a diagonal matrix (i.e.,matrix in which the components other than the diagonal components are 0)as described below.

$\begin{matrix}{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & 0 & \cdots & 0 \\0 & P_{i,u,1,1} & \ddots & \vdots \\\vdots & \ddots & \ddots & 0 \\0 & \cdots & \cdots & P_{i,u,{N_{{SL},\mu} - 1},{N_{{SL},\mu} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 4} \right\rbrack\end{matrix}$

Here, a communication target of the transmission apparatus i is notlimited to only the reception apparatus u, but can also be anotherreception apparatus v. Therefore, for example, a signal x_(i,u) directedto the reception apparatus u and a signal x_(i,v) directed to the otherreception apparatus v can be transmitted in the same radio resource.These signals are multiplexed for each transmission antenna port, forexample, on the basis of superposition multiplexing, superpositioncoding (SPC), multiuser superposition transmission (MUST),non-orthogonal multiple access (NOMA), or the like. A multiplexed signalx_(i) transmitted from the transmission apparatus i is expressed asfollows.

$\begin{matrix}{x_{i} = {\sum\limits_{u \in U_{i}}x_{i,u}}} & \left\lbrack {{Math}.\mspace{14mu} 5} \right\rbrack\end{matrix}$

Note that, in the equation shown above, U_(i) represents a set ofindexes of the reception apparatus u for which the transmissionapparatus i multiplexes signals. In addition, the following processingwill be described, focusing on signal processing for each transmissionantenna port p and each symbol block g.

A signal for each transmission antenna port is converted into afrequency component by performing time-frequency transform processing(e.g., DFT, FFT, or the like) on a time symbol sequence. Here, if thenumber of data symbols included in the symbol block g is represented asN_(DS,g), a frequency component x⁻ _(i,p,g) of a time symbol sequencex_(i,p,g) of the symbol block g transmitted from the transmissionapparatus i via a transmission port p can be expressed as follows. Notethat, in the present description, it is assumed that “x⁻” represents aletter obtained by overlining “x.” In addition, it is assumed that F_(N)shown in the following equation represents a Fourier transform matrixhaving size N.

$\begin{matrix}{\mspace{76mu} {\begin{matrix}{{\overset{\_}{x}}_{i,p,g} = {F_{N_{{DS},g}}x_{i,p,g}^{T}}} \\{= \left\lbrack {{\overset{\_}{x}}_{i,p,g,0}\mspace{14mu} \cdots \mspace{14mu} {\overset{\_}{x}}_{i,p,g,{N_{{DS},g} - 1}}} \right\rbrack^{T}}\end{matrix}\mspace{76mu} {x_{i,p,g} = \left\lbrack {x_{i,p,g,0}\mspace{14mu} \cdots \mspace{14mu} x_{i,p,g,{N_{{DS},g} - 1}}} \right\rbrack}{F_{N} = \begin{bmatrix}{\exp \left( {{- j}\; 2\pi \frac{0 \cdot 0}{N}} \right)} & \cdots & {\exp \left( {{- j}\; 2\pi \frac{0 \cdot \left( {N - 1} \right)}{N}} \right)} \\\vdots & \ddots & \vdots \\{\exp \left( {j\; 2\pi \frac{\left( {N -} \right) \cdot 0}{N}} \right)} & \cdots & {\exp \left( {{- j}\; 2\pi \frac{\left( {N - 1} \right) \cdot \left( {N - 1} \right)}{N}} \right)}\end{bmatrix}}}} & \left\lbrack {{Math}.\mspace{14mu} 6} \right\rbrack\end{matrix}$

A converted frequency component x⁻ _(i,p,g) is mapped to a resourceelement along the frequency direction of a resource block. It is alsopossible to process this processing of mapping the frequency componentx⁻ _(i,p,g) to a resource element as shown in the following equation.

$\begin{matrix}\begin{matrix}{{\overset{\sim}{x}}_{i,p,g} = {A_{i,p,g}{\overset{\_}{x}}_{i,p,g}}} \\{= \left\lbrack {{\overset{\sim}{x}}_{i,p,g,0}\mspace{14mu} \cdots \mspace{14mu} {\overset{\sim}{x}}_{i,p,g,{N_{IDFT} - 1}}} \right\rbrack^{T}}\end{matrix} & \left\lbrack {{Math}.\mspace{14mu} 7} \right\rbrack\end{matrix}$

Note that, in the equation shown above, x⁻ _(i,p,g) represents afrequency component after the frequency component x⁻ _(i,p,g) is mappedto a resource element. Note that, in the present description, it isassumed that “x⁻” represents a letter obtained by providing tilde to thetop of “x.” In addition, in the equation shown above, A represents afrequency mapping matrix having size N_(IDFT)×N_(DS,g). Here, in thecase where a frequency component x^(˜) _(i,p,g,k′) of a component k′after frequency conversion is mapped to a frequency component x⁻_(i,p,g),k corresponding to a component k, a (k, k′) component of afrequency mapping matrix is 0. It is desirable that the sum of theelements in each row of the matrix A be less than or equal to 1, and thesum of the elements in each column be less than or equal to 1.

Next, frequency-time conversion processing (e.g., IDFT, IFFT, or thelike) is performed on the frequency component x^(˜) _(i,p,g) mapped to aresource element, the frequency component x^(˜) _(i,p,g) is convertedinto a time sequence again. Here, a time symbol sequence d^(˜) _(i,p,g)into which x^(˜) _(i,p,g) is converted is expressed as follows. Notethat, in the present description, it is assumed that “d^(˜)” representsa letter obtained by providing tilde to the top of “d.” In addition, inthe equation shown below, F^(H) represents a Hermitian matrix of F.

$\begin{matrix}\begin{matrix}{{\overset{\sim}{d}}_{i,p,g} = {F_{N_{IDFT}}^{H}{\overset{\sim}{x}}_{i,p,g}}} \\{= \left\lbrack {{{\overset{\sim}{d}}_{i,p,g}(0)}\mspace{14mu} \cdots \mspace{14mu} {{\overset{\sim}{d}}_{i,p,g}\left( {N_{IDFT} - 1} \right)}} \right\rbrack^{T}}\end{matrix} & \left\lbrack {{Math}.\mspace{14mu} 8} \right\rbrack\end{matrix}$

In addition, a CP or a known symbol sequence is added for each symbolblock to the time symbol sequence d^(˜) _(i,p,g) converted from afrequency component to a time sequence. For example, in the case where aCP having length N_(CP,g) is added to the time symbol sequence d^(˜)_(i,p,g), a symbol sequence d̂_(i,p,g) to which a CP has been added isexpressed as follows. Note that it is assumed that “d̂” represents aletter obtaining by providing a hat to “d.”

$\begin{matrix}\begin{matrix}{{\hat{d}}_{i,p,g} = \left\lbrack {{{\hat{d}}_{i,p,g}(0)}\mspace{14mu} \cdots \mspace{14mu} {{\hat{d}}_{i,p,g}\left( {N_{{IDFT},g} + N_{{CP},g} - 1} \right)}} \right\rbrack^{T}} \\{= \left\lbrack {{{\overset{\sim}{d}}_{i,p,g}\left( {N_{{IDFT},g} - N_{{CP},g}} \right)}\mspace{14mu} \cdots \mspace{14mu} {{\overset{\sim}{d}}_{i,p,g}\left( {N_{{IDFT},g} - 1} \right)}\mspace{14mu} {{\overset{\sim}{d}}_{i,p,g}(0)}\mspace{14mu} \cdots \mspace{14mu} {{\overset{\sim}{d}}_{i,p,g}\left( {N_{{IDFT},g} - 1} \right)}} \right\rbrack^{T}}\end{matrix} & \left\lbrack {{Math}.\mspace{14mu} 9} \right\rbrack\end{matrix}$

Next, FTN processing is performed on the symbol sequence d̂_(i,p,g) towhich a CP has been added. Note that the FTN processing includesover-sampling processing and pulse shaping filtering processing. First,focus is placed on over-sampling processing. If the number ofover-samples is represented as Nos, a time symbol sequence d′_(i,p)[n]after over-sampling is expressed as follows. Note that, in the equationshown below, an index g of a symbol block is omitted.

$\begin{matrix}{{d_{i,p}^{\prime}\lbrack n\rbrack} = \left\{ \begin{matrix}{{\hat{d}}_{i,p}\left( \frac{n}{N_{OS}} \right)} & , & {{n = 0},N_{OS},{2N_{OS}},\cdots} \\0 & , & {otherwise}\end{matrix} \right.} & \left\lbrack {{Math}.\mspace{14mu} 10} \right\rbrack\end{matrix}$

In addition, pulse shaping processing that takes FTN into considerationis performed on the time symbol sequence d′_(i,p)[n] afterover-sampling. In the case where the filter factor of a pulse shapefilter is represented as Ψ_(i,p)(t), an output of pulse shapingprocessing is expressed as follows.

$\begin{matrix}{{s_{i,p}(t)} = {\sum\limits_{n}{{d_{i,p}^{\prime}\lbrack n\rbrack}{\psi_{i,p}\left( {t - {n\; \tau_{i,p}T}} \right)}}}} & \left\lbrack {{Math}.\mspace{14mu} 11} \right\rbrack\end{matrix}$

Here, in the case where the symbol length is represented as T, 1/Trepresents the symbol rate. In addition, τ_(i,p) is a coefficientregarding FTN, and has a real-number value within a range of0<τ_(i,p)≤1. Note that, in the following description, the coefficientτ_(i,p) will be referred to as “compression coefficient” for the sake ofconvenience in some cases. It is also possible to regard the compressioncoefficient as a coefficient that connects the symbol length T to asymbol arrangement (i.e., symbol intervals) T′ in FTN. In general,0<T′≤T holds, and a relationship of τ_(i,p)=T′/T≤1 is obtained.

Note that, in the conventional modulation scheme applied in thestandards such as LTE/LTE-A, it is preferable that the filter factor bea filter (what is called, a filter (Nyquist filter) compliant with aNyquist criterion) of a coefficient that has a value of zero per time Twhen the value at time zero peaks. A specific example of the filtercompliant with a Nyquist criterion includes a raised-cosine (RC) filter,a root-raised-cosine (RRC) filter, and the like. Note that, in the casewhere a filter compliant with a Nyquist criterion in the above-describedtransmission processing in which FTN can be applied, τ_(i,p)=1 makes theinter-symbol interference of the generated signal itself zero inprinciple.

Analog and radio frequency (RF) processing is then performed on thesignal (i.e., output of pulse shaping filtering processing) on which FTNprocessing has been performed, and the signal is sent to a transmissionantenna (antenna port).

The above describes an example of transmission signal processing in thecase where FTN is employed.

(4) FTN Transmission Scheme in which Changing Compression Coefficientfor Each Cell (Cell-Specific)

Next, an example of a transmission scheme in the case where thecompression coefficient τ_(i,p) in FTN is changed for each cell(cell-specific) will be described.

In FTN, as the compression coefficient τ_(i,p) decreases, the influenceof inter-symbol interference contained in FTN itself increases (in otherwords, the symbol intervals are narrower). Meanwhile, in the so-calledradio communication system, multiplex transmission, the nonlinearfrequency characteristic of a propagation path, and the like can causeinter-symbol interference even in a radio propagation path. Therefore,in the radio communication system in which FTN is employed, it can benecessary to take the inter-symbol interference in the radio propagationpath into consideration in addition to the influence of inter-symbolinterference contained in FTN itself. In view of such circumstances, thecommunication system according to the present embodiment takes intoconsideration the load of the processing of addressing inter-symbolinterference in a reception apparatus, and is configured to be capableof adaptively adjusting a compression coefficient. Such a configurationmakes it possible to balance between the load in a reception apparatusand frequency use efficiency.

(a) Adjustment of Compression Coefficient According to Frequency ofChannel

First, with reference to FIGS. 11 and 12, an example of the case where acompression coefficient is adjusted in accordance with the frequency ofa channel will be described.

For example, FIG. 11 illustrates an example of the relationship betweenthe frequency of a channel, the level of inter-symbol interference, anda compression coefficient. In general, the delay spread caused by aradio propagation path increases as frequency is lower because of theinfluence of a reflected wave, a diffracted wave, and the like, whilethe delay spread decreases as frequency is higher because of itstendency to propagate more straightly. That is, the influence of theinter-symbol interference in the radio propagation path tends toincrease as frequency is lower, and decrease as frequency is higher.

It is estimated from such a characteristic that even the processing ofaddressing the inter-symbol interference in the radio propagation pathimposes a relatively lighter load in a channel of high frequency.Therefore, the load that is no longer spent in addressing theinter-symbol interference in the radio propagation path is spent in theprocessing of addressing inter-symbol interference contained in FTN.This makes it possible to suppress increase in the load in a receptionapparatus and efficiently improve frequency use efficiency.

Specifically, as illustrated in FIG. 11, it is desirable to employ theconfiguration in which a smaller compression coefficient is applied to achannel of higher frequency (in other words, the configuration in whicha larger compression coefficient is applied to a channel of lowerfrequency).

As a more specific example, FIG. 11 illustrates an example of the casewhere a component carrier (CC) 0 to a CC 3 are used as CCs for atransmission apparatus to transmit data. Note that, in the case wherethe respective frequency channels corresponding to the CC 0 to the CC 3are represented as channels f0 to f3, it is assumed that the magnituderelationship between the channels f0 to f3 with respect to frequency isf0<f1<f2<f3. Note that, in the example illustrated in FIG. 11, it isassumed that the CC 0 is set as a primary CC (PCC), and the CC 1 to theCC 3 are each set as a secondary CC (SCC).

Here, in the case where the respective compression coefficients appliedin the CC 0 to the CC 3 are represented as τ0 to τ3, the magnituderelationship between the compression coefficients τ0 to τ3 in theexample illustrated in FIG. 11 is τ0≥τ1≥τ2≥τ3.

Next, with reference to FIG. 12, an example of processing of setting acompression coefficient in accordance with the frequency of a channelwill be described. FIG. 12 is a flowchart illustrating an example ofprocessing of setting a compression coefficient in accordance with thefrequency of a channel. Note that, in the present description,description will be made using the case where a transmission apparatusplays a main role to set a compression coefficient as an example.Meanwhile, the main role of the processing is not necessarily limited toa transmission apparatus. As a specific example, in the case where FTNis applied to an uplink, a base station corresponding to a receptionapparatus may set a compression coefficient.

Specifically, a transmission apparatus first checks the frequency bandof a target CC (S101). The transmission apparatus then just has to setthe compression coefficient corresponding to the target CC in accordancewith the frequency band of the CC (S103).

With reference to FIGS. 11 and 12, the above describes an example of thecase where a compression coefficient is adjusted in accordance with thefrequency of a channel.

(b) Adjustment of Compression Coefficient According to Component Carrier

Next, with reference to FIGS. 13 and 14, an example of the case where acompression coefficient is adjusted in accordance with whether a targetCC is a PCC or an SCC will be described.

For example, FIG. 13 illustrates another example of the relationshipbetween the frequency of a channel, the level of inter-symbolinterference, and a compression coefficient. It is desirable that PCCsbe placed in the state in which it is basically possible for all theterminals in a cell to transmit and receive the PCCs. In addition, fromthe perspective of coverage, it is desirable that a PCC be as low afrequency channel as possible. For example, in the example illustratedin FIG. 11, the PCC is the lowest frequency channel among the targets.Note that the PCC corresponds to an example of a CC of higher priority.

Because of the above-described characteristic of a PCC, it is moredesirable to apply a larger value than that of another CC (SCC) to thecompression coefficient corresponding to the PCC in order to lessen theinter-symbol interference caused by FTN. Moreover, setting a compressioncoefficient of 1 (τ=1) for the PCC also makes it possible to furtherimprove the reliability of the transmission and reception of data viathe PCC. Note that setting 1 as the compression coefficient issubstantially the same as applying no FTN. In principle, theinter-symbol interference accompanying FTN processing does not occur.

For example, FIG. 13 illustrates an example of the case where the CC 0to the CC 3 are used as CCs. Note that, in the case where the respectivefrequency channels corresponding to the CC 0 to the CC 3 are representedas channels f0 to f3, it is assumed that the magnitude relationshipbetween the channels f0 to f3 with respect to frequency is f0<f1<f2<f3.Note that, in the example illustrated in FIG. 11, it is assumed that theCC 1 is set as a primary CC (PCC), and the CC 0, CC 2, and the CC 3 areeach set as a secondary CC (SCC). That is, FIG. 13 illustrates anexample of the case where the PCC is not the lowest frequency channelamong the targets. Note that the respective compression coefficientsapplied in the CC 0 to the CC 3 are represented as τ0 to τ3.

Specifically, in the case of the example illustrated in FIG. 13, thecompression coefficient τ1 applied in the PCC (i.e., channel f1) is setto be the highest (e.g., 1 is set therefor), and the compressioncoefficients τ0, τ2, and τ3 applied in the other CCs (SCCs) are set tobe less than or equal to the compression coefficient τ1. Such aconfiguration makes it possible to secure the reliability of thetransmission and reception of data via the PCC. Note that, as themagnitude relationship between the compression coefficients TO, τ2, andτ3, smaller compression coefficients may be set with increase infrequency similarly to the example illustrated in FIG. 11.

Next, with reference to FIG. 14, an example of processing of setting acompression coefficient in accordance with whether a target CC is a PCCor an SCC will be described. FIG. 14 is a flowchart illustrating anexample of processing of setting a compression coefficient in accordancewith whether a target CC is a PCC or an SCC. Note that, in the presentdescription, description will be made using the case where atransmission apparatus plays a main role to set a compressioncoefficient as an example.

Specifically, a transmission apparatus first determines whether or not atarget CC is a PCC (i.e., any of PCC and SCC) (S151). In the case wherethe target CC is a PCC (S151, YES), the transmission apparatus sets acompression coefficient (e.g., τ=1) for a PCC as the compressioncoefficient corresponding to the CC (S153). In addition, in the casewhere the target CC is not a PCC (S151, NO), the transmission apparatuschecks the frequency band of the CC (S155). The transmission apparatusthen sets the compression coefficient corresponding to the target CC inaccordance with the frequency band of the CC (S157).

With reference to FIGS. 13 and 14, the above describes an example of thecase where a compression coefficient is adjusted in accordance withwhether a target CC is a PCC or an SCC.

(c) Example of Control Table for Setting Compression Coefficient

Next, an example of a control table for the subject (e.g., transmissionapparatus) that sets a compression coefficient to set a compressioncoefficient for a target CC as described above in accordance withwhether or not the CC is a PCC, or a condition of the CC such asfrequency will be described.

Specifically, as shown below as Table 1, the range of a frequency bandand the value of a compression coefficient may be associated fixedlywith each other in advance, and managed as a control table. In addition,in the control table, the values of compression coefficients may beindividually set for a PCC and an SCC.

TABLE 1 Example of Association of Range of Frequency Band and Value ofCompression Coefficient Range of Frequency f of CC Primary CC SecondaryCC F0 ≤ f < F1 τpcell0 τscell0 F1 ≤ f < F2 τpcell1 τscell1 F2 ≤ f < F3τpcell2 τscell2 F3 ≤ f < F4 τpcell3 τscell3 . . . . . . . . .

A frequency f in Table 1 is, for example, at least one of a centralfrequency, a lower limit frequency, and an upper limit frequency of acomponent carrier. For example, in the example shown above as Table 1,in the case where a target CC is a PCC, compression coefficientsτpcell0, τpcell1, τpcell2, τpcell4, . . . are set in accordance with therange of a frequency f corresponding to the CC. Note that it isdesirable at this time that the magnitude relationship between therespective compression coefficients be τpcell0≥τpcell1≥τpcell2≥τpcell4≥. . . . Note that 1 may be set as the compression coefficientcorresponding to a PCC.

In addition, in the example shown above as Table 1, in the case where atarget CC is a SCC, compression coefficients τscell0, τscell1, τscell2,τscell4, . . . are set in accordance with the range of the frequency fcorresponding to the CC. Note that it is desirable at this time that themagnitude relationship between the respective compression coefficientsbe τscell0≥τscell1≥τscell2≥τscell4≥ . . . . In addition, it is desirablethat a smaller value than that of the compression coefficientcorresponding to a PCC be set as the compression coefficientcorresponding to an SCC. In addition, Table 1 shows a table in whichranges of the frequency bandwidth and values of the compressioncoefficients are fixedly associated with each other in advance, but thepresent disclosure is not limited thereto. For example, a control tablein which, instead of the value of the frequency f, a component carrieror a channel number (frequency band index) of a frequency channel andthe compression coefficient are associated with each other may be used.

(5) Example of Sequence for Changing Compression Coefficient for EachCell (Cell-Specific)

Next, an example of a communication sequence between the base station100 and the terminal apparatus 200 in the case where the compressioncoefficient τ_(i,p) in FTN is changed for each cell (cell-specific) willbe described.

(a) Regarding Application to Downlink

First, with reference to FIGS. 15 and 16, an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where FTN is employed for a downlink will be described.

On a downlink, the base station 100 adjusts the symbol intervals betweensymbols in data transmitted via a shared channel (data channel) on thebasis of the compression coefficient τ_(i,p) decided for each cell. Inthis case, the base station 100 notifies the terminal apparatus 200 ofthe compression coefficient τ_(i,p) decided for each cell as a parameterrelated to FTN. This allows the terminal apparatus 200 to decode thedata (i.e., data on which FTN processing has been performed) transmittedfrom the base station 100 on the basis of the compression coefficientτ_(i,p) of which the terminal apparatus 200 is notified by the basestation 100.

Note that, as long as the terminal apparatus 200 is capable ofrecognizing the compression coefficient τ_(i,p) by the timing at whichthe data on which the base station 100 has performed FTN mappingprocessing on the basis of the compression coefficient τ_(i,p) isdecoded, the timing at which the base station 100 notifies the terminalapparatus 200 of an FTN parameter is not limited in particular. Forexample, an example of the timing at which the base station 100 notifiesthe terminal apparatus 200 of an FTN parameter includes RRC connectionreconfiguration, system information, downlink control information (DCI),and the like. Especially in the case where the compression coefficientτ_(i,p) is set for each cell (cell-specific), it is more desirable thatthe base station 100 notify the terminal apparatus 200 of thecompression coefficient τ_(i,p) in RRC connection reconfiguration orsystem information.

(a-1) Notification Through RRC Connection Reconfiguration

First, with reference to FIG. 15, as an example of a communicationsequence in the case where FTN is employed for a downlink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter. FIG. 15 is an explanatorydiagram for describing an example of a communication sequence in thecase where FTN is employed for a downlink, and illustrates an example ofthe case where the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter.

More specifically, when transmitting an RRC connection reconfigurationmessage to the terminal apparatus 200, the base station 100 notifies theterminal apparatus 200 of an FTN parameter (e.g., compressioncoefficient τ_(i,p)) set for each cell (S201). When receiving the RRCconnection reconfiguration message from the base station 100, theterminal apparatus 200 transmits an RRC connection reconfigurationcomplete message indicating that the terminal apparatus 200 hassucceeded in correctly receiving the message to the base station 100(S203). In this procedure, the terminal apparatus 200 becomes capable ofrecognizing the compression coefficient τ_(i,p) (i.e., compressioncoefficient τ_(i,p) for decoding (FTN de-mapping) the data transmittedfrom the base station 100) used by the base station 100 to perform FTNmapping processing on transmission data.

Next, the base station 100 uses a physical downlink control channel(PDCCH) to transmit allocation information of a physical downlink sharedchannel (PDSCH) that is the frequency (e.g., resource block (RB) andtime resource (e.g., subframe (SF)) of data transmission and receptionto the terminal apparatus 200 (S205). The terminal apparatus 200 thathas received the PDCCH decodes the PDCCH, thereby becoming capable ofrecognizing the frequency and time resource (PDSCH) allocated toterminal apparatus 200 itself (S207).

Next, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal, and transmits the transmission signal onto adesignated PDSCH resource (S209). The terminal apparatus 200 receivesthe PDSCH designated by the allocation information from the base station100, and performs various kinds of demodulation and decoding processingincluding FTN de-mapping processing based on the FTN parameter of whichthe terminal apparatus 200 has been notified by the base station 100 ona reception signal to extract the data transmitted from the base station100 (S211). Note that, in the case where the terminal apparatus 200 hassucceeded in decoding the data with no error on the basis of errordetection such as CRC, the terminal apparatus 200 may return an ACK tothe base station 100. In addition, in the case where the terminalapparatus 200 has detected an error on the basis of error detection suchas CRC, the terminal apparatus 200 may return a NACK to the base station100 (S213).

With reference to FIG. 15, the above makes, as an example of acommunication sequence in the case where FTN is employed for a downlink,description, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter.

(a-2) Notification Through System Information

Next, with reference to FIG. 16, as an example of a communicationsequence in the case where FTN is employed for a downlink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses system information (SIB: system information block)to notify the terminal apparatus 200 of an FTN parameter. FIG. 16 is anexplanatory diagram for describing an example of a communicationsequence in the case where FTN is employed for a downlink, andillustrates an example of the case where the base station 100 usessystem information to notify the terminal apparatus 200 of an FTNparameter.

More specifically, the base station 100 broadcasts an SIB message toeach terminal apparatus 200 positioned in the cell 10. At this time, thebase station 100 includes an FTN parameter in the SIB message to notifyeach terminal apparatus 200 positioned in the cell 10 of the FTNparameter (S251). This allows the terminal apparatus 200 to recognizethe compression coefficient τ_(i,p) used by the base station 100 toperform FTN mapping processing on transmission data. Note that, asdescribed above, an SIB message is broadcast to each terminal apparatus200 positioned in the cell 10, so that the terminal apparatus 200 makesno response to the SIB message for the base station 100. In other words,in the example illustrated in FIG. 16, the base station 100unidirectionally notifies the terminal apparatus 200 positioned in thecell 10 of various kinds of parameter information (e.g., FTN parameter).

Note that the communication sequences represented by reference numeralsS253 to S261 in FIG. 16 are similar to the communication sequencesrepresented by reference numerals S205 to S213 in FIG. 15, so thatdetailed description will be omitted.

With reference to FIG. 16, the above makes, as an example of acommunication sequence in the case where FTN is employed for a downlink,description, focusing especially on an example of the case where thebase station 100 uses system information to notify the terminalapparatus 200 of an FTN parameter.

(b) Regarding Application to Uplink

Next, with reference to FIGS. 17 and 18, an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where FTN is employed for an uplink will be described.

On an uplink, the terminal apparatus 200 serves as a transmissionapparatus, and the base station 100 serves as a reception apparatus.Meanwhile, on an uplink, the base station 100 takes charge in thenotification of an FTN parameter and the allocation of a physical uplinkshared channel (PUSCH) resource similarly to a downlink. That is, in thesituation in which parameter setting set for each cell is performed(e.g., setting of an FTN parameter), it is more desirable in terms of anapparatus group in one area referred to as cell that the base station100 play the role of the notification of various kinds of informationand various kinds of control.

Note that, as long as the terminal apparatus 200 is capable ofrecognizing the compression coefficient τ_(i,p) applied to FTN mappingprocessing by the timing at which the FTN mapping processing isperformed on transmission target data, the timing at which the basestation 100 notifies the terminal apparatus 200 of an FTN parameter isnot limited in particular. For example, an example of the timing atwhich the base station 100 notifies the terminal apparatus 200 of an FTNparameter includes RRC connection reconfiguration, system information,downlink control information (DCI), and the like. Especially in the casewhere the compression coefficient τ_(i,p) is set for each cell(cell-specific), it is more desirable that the base station 100 notifythe terminal apparatus 200 of the compression coefficient τ_(i,p) in RRCconnection reconfiguration or system information.

(b-1) Notification Through RRC Connection Reconfiguration

First, with reference to FIG. 17, as an example of a communicationsequence in the case where FTN is employed for an uplink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter. FIG. 17 is an explanatorydiagram for describing an example of a communication sequence in thecase where FTN is employed for an uplink, and illustrates an example ofthe case where the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter.

More specifically, when transmitting an RRC connection reconfigurationmessage to the terminal apparatus 200, the base station 100 notifies theterminal apparatus 200 of an FTN parameter (e.g., compressioncoefficient τ_(i,p)) set for each cell (S301). When receiving the RRCconnection reconfiguration message from the base station 100, theterminal apparatus 200 transmits an RRC connection reconfigurationcomplete message indicating that the terminal apparatus 200 hassucceeded in correctly receiving the message to the base station 100(S303). In this procedure, the terminal apparatus 200 becomes capable ofrecognizing the compression coefficient τ_(i,p) used to perform FTNmapping processing on data to be transmitted to the base station 100.

Next, the terminal apparatus 200 uses a physical uplink control channel(PUCCH) to request the base station 100 in to allocate a physical uplinkshared channel (PUSCH) that is a frequency and time resource fortransmitting and receiving data. The base station 100 that has receivedthe PUCCH decodes the PUCCH to recognize the contents of the requestfrom the terminal apparatus 200 to allocate a frequency and timeresource (S305).

Next, the base station 100 uses a physical downlink control channel(PDCCH) to transmit allocation information of a PUSCH to the terminalapparatus 200 (S307). The terminal apparatus 200 that has received thePDCCH decodes the PDCCH, thereby becoming capable of recognizing thefrequency and time resource (PUSCH) allocated to terminal apparatus 200itself (S309).

Next, the terminal apparatus 200 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter of which the terminal apparatus 200has been notified by the base station 100 to generate a transmissionsignal. The terminal apparatus 200 then transmits the generatedtransmission signal onto the PUSCH resource designated by the allocationinformation from the base station 100 (S311). The base station 100receives the designated PUSCH, and performs various kinds ofdemodulation and decoding processing including the FTN de-mappingprocessing based on the FTN parameter set for each cell on a receptionsignal to extract the data transmitted from the terminal apparatus 200(S313). Note that, in the case where the base station 100 has succeededin decoding the data with no error on the basis of error detection suchas CRC, the base station 100 may return an ACK to the terminal apparatus200. In addition, in the case where the base station 100 has detected anerror on the basis of error detection such as CRC, the base station 100may return a NACK to the terminal apparatus 200 (S315).

With reference to FIG. 17, the above makes, as an example of acommunication sequence in the case where FTN is employed for an uplink,description, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter.

(b-2) Notification Through System Information

Next, with reference to FIG. 18, as an example of a communicationsequence in the case where FTN is employed for an uplink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses system information to notify the terminalapparatus 200 of an FTN parameter. FIG. 18 is an explanatory diagram fordescribing an example of a communication sequence in the case where FTNis employed for an uplink, and illustrates an example of the case wherethe base station 100 uses system information to notify the terminalapparatus 200 of an FTN parameter.

More specifically, the base station 100 broadcasts an SIB message toeach terminal apparatus 200 positioned in the cell 10. At this time, thebase station 100 includes an FTN parameter in the SIB message to notifyeach terminal apparatus 200 positioned in the cell 10 of the FTNparameter (S351). This allows the terminal apparatus 200 to recognizethe compression coefficient τ_(i,p) used to perform FTN mappingprocessing on data to be transmitted to the base station 100. Note that,similarly to the case of a downlink, an SIB message is broadcast to eachterminal apparatus 200 positioned in the cell 10, so that the terminalapparatus 200 makes no response to the SIB message for the base station100. In other words, in the example illustrated in FIG. 18, the basestation 100 unidirectionally notifies the terminal apparatus 200positioned in the cell 10 of various kinds of parameter information(e.g., FTN parameter).

Note that the communication sequences represented by reference numeralsS353 to S363 in FIG. 18 are similar to the communication sequencesrepresented by reference numerals S305 to S315 in FIG. 17, so thatdetailed description will be omitted.

With reference to FIG. 18, the above makes, as an example of acommunication sequence in the case where FTN is employed for an uplink,description will be made, focusing especially on an example of the casewhere the base station 100 uses system information to notify theterminal apparatus 200 of an FTN parameter.

In a case where the compression coefficient is controlledcell-specifically, a semi-static case and a dynamic case are consideredas updating units of coefficients in the time direction. As thesemi-static case, updating the coefficient in units of a plurality ofsubframes, units of one radio frame, or units of a plurality of radioframes is considered. By updating the coefficient in this way, the basestation 100 (the transmission apparatus) and the terminal apparatus 200(the reception apparatus) can continue communication by continuing atime of a degree which is setting performed once. In addition, byupdating the coefficient in this way, an effect of suppressing anincrease in overhead can be expected in the base station 100 and theterminal apparatus 200.

On the other hand, as the dynamic updating case, for example, updatingthe coefficient in units of one subframe or units of a plurality ofsubframes is considered. Alternatively, as the dynamic updating case,updating the coefficient aperiodically at each subframe can also beconsidered. In the dynamic updating case, the transmission apparatus andthe reception apparatus can set a value of the compression coefficientin accordance with information transmitted with a physical controlchannel (PDCCH or ePDCCH). By updating the coefficient in this way, thebase station 100 (the transmission apparatus) and the terminal apparatus200 (the reception apparatus) can associate parameters flexibly inaccordance with a change in a radio wave propagation environment.

(c) Regarding Application to Communication System in which CarrierAggregation is Employed

Next, an example of a communication sequence between the base station100 and the terminal apparatus 200 in the case where FTN is employed fora communication system in which carrier aggregation is employed will bedescribed.

In the above-described example of a communication sequence on an uplinkand a downlink, a frequency channel used for the notification of an FTNparameter is not mentioned in particular. Meanwhile, in the case where aplurality of frequency channels are used in a cell like carrieraggregation, it is possible to use a desired channel for thenotification of an FTN parameter.

Accordingly, in the present description, an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where a plurality of frequency channels are used in a cell willbe described on the basis of the example illustrated in FIG. 19. FIG. 19is a diagram illustrating an example of a frequency channel used forcommunication between the base station 100 and the terminal apparatus200 in a communication system including carrier aggregation.Specifically, FIG. 19 illustrates an example of the case where the CC 0and the CC 1 are used as CCs for a transmission apparatus to transmitdata. Note that, in the case where the respective frequency channelscorresponding to the CC 0 and the CC 1 are represented as channels f0and f1, it is assumed that the magnitude relationship between thechannels f0 and f1 with respect to frequency is f0<f1. In addition, inthe example illustrated in FIG. 19, it is assumed that the CC 0 is setas a PCC, and the CC 1 is set as an SCC.

(c-1) Notification of FTN Parameter Through Channel to which FTN isApplied

First, with reference to FIGS. 20 and 21, an example of the case wherethe base station 100 uses a frequency channel to which FTN is applied tonotify the terminal apparatus 200 of an FTN parameter will be described.FIGS. 20 and 21 are explanatory diagrams each for describing an exampleof a communication sequence in the case where FTN is employed for thedownlink in the communication system in including carrier aggregation.Note that FIGS. 20 and 21 each illustrate an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where the base station 100 uses a frequency channel to whichFTN is applied to notify the terminal apparatus 200 of an FTN parameter.

For example, similarly to the example described with reference to FIG.15, FIG. 20 illustrates an example of the case where FTN is employed fora downlink, and the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter. Note that thecommunication sequences represented by reference numerals S401 to S413in FIG. 20 are similar to the communication sequences represented byreference numerals S201 to S213 in FIG. 15, so that detailed descriptionwill be omitted. In addition, FIG. 20 illustrates an example of the casewhere FTN is applied to the channel f1 (i.e., CC 1 that is an SCC).

Specifically, in the example illustrated in FIG. 20, the base station100 uses, as represented by a reference numeral S401, the channel f1 totransmit an RRC connection reconfiguration message to the terminalapparatus 200. At this time, the base station 100 notifies the terminalapparatus 200 of an FTN parameter (e.g., compression coefficientτ_(i,p)) set for each cell.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S409, the channel f1 to transmit the transmissionsignal onto the PDSCH resource designated for the terminal apparatus200.

In addition, as another example, similarly to the example described withreference to FIG. 16, FIG. 21 illustrates an example of the case whereFTN is employed for a downlink, and the base station 100 uses systeminformation to notify the terminal apparatus 200 of an FTN parameter.Note that the communication sequences represented by reference numeralsS451 to S461 in FIG. 21 are similar to the communication sequencesrepresented by reference numerals S251 to S261 in FIG. 16, so thatdetailed description will be omitted. In addition, FIG. 21 illustratesan example of the case where FTN is applied to the channel f1 (i.e., CC1 that is an SCC).

Specifically, in the example illustrated in FIG. 21, the base station100 uses, as represented by a reference numeral S451, the channel f1 tobroadcast an SIB message to each terminal apparatus 200 positioned inthe cell 10. At this time, the base station 100 includes an FTNparameter in the SIB message to notify each terminal apparatus 200positioned in the cell 10 of the FTN parameter.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S457, the channel f1 to transmit the transmissionsignal onto the PDSCH resource designated for the terminal apparatus200.

With reference to FIGS. 20 and 21, the above describes an example of thecase where the base station 100 uses a frequency channel to which FTN isapplied to notify the terminal apparatus 200 of an FTN parameter. Notethat, although the above focuses on an example of the case where FTN isapplied to a downlink for description, it goes without saying that thesame applies to the case where FTN is applied to an uplink.

(c-2) Notification of FTN Parameter Through Predetermined Channel

Next, with reference to FIGS. 22 and 23, an example of the case wherethe base station 100 uses a predetermined frequency channel to notifythe terminal apparatus 200 of an FTN parameter will be described. FIGS.22 and 23 are explanatory diagrams each for describing an example of acommunication sequence in the case where FTN is employed for a downlinkin the communication system in which carrier aggregation is employed.Note that FIGS. 22 and 23 each illustrate an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where the base station 100 uses a predetermined frequencychannel to notify the terminal apparatus 200 of an FTN parameter. Inaddition, in the present description, description will be made, focusingespecially on the case where the base station 100 uses another frequencychannel different from a frequency channel to which FTN is applied tonotify the terminal apparatus 200 of an FTN parameter.

For example, similarly to the example described with reference to FIG.15, FIG. 22 illustrates an example of the case where FTN is employed fora downlink, and the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter. Note that thecommunication sequences represented by reference numerals S501 to S513in FIG. 22 are similar to the communication sequences represented byreference numerals S201 to S213 in FIG. 15, so that detailed descriptionwill be omitted.

FIG. 22 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC), and the base station 100 usesthe channel f0 (i.e., CC 0 that is a PCC) to notify the terminalapparatus 200 of an FTN parameter. In the example illustrated in FIG.22, in the case where the base station 100 transmits or receivesinformation for controlling communication with the terminal apparatus200, the base station 100 uses the channel f0 (i.e., PCC), and in thecase where the base station 100 transmits live data, the base station100 uses the channel f1 (i.e., SCC) to which FTN is applied.

More specifically, in the example illustrated in FIG. 22, the basestation 100 uses, as represented by a reference numeral S501, thechannel f0 (i.e., PCC) to transmit an RRC connection reconfigurationmessage to the terminal apparatus 200. At this time, the base station100 notifies the terminal apparatus 200 of an FTN parameter (e.g.,compression coefficient τ_(i,p)) set for each cell.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S509, the channel f1 (i.e., SCC) to transmit thetransmission signal onto the PDSCH resource designated for the terminalapparatus 200.

In addition, as another example, similarly to the example described withreference to FIG. 16, FIG. 23 illustrates an example of the case whereFTN is employed for a downlink, and the base station 100 uses systeminformation to notify the terminal apparatus 200 of an FTN parameter.Note that the communication sequences represented by reference numeralsS551 to S561 in FIG. 23 are similar to the communication sequencesrepresented by reference numerals S251 to S261 in FIG. 16, so thatdetailed description will be omitted.

FIG. 23 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC), and the base station 100 usesthe channel f0 (i.e., CC 0 that is a PCC) to notify the terminalapparatus 200 of an FTN parameter. In the example illustrated in FIG.23, in the case where the base station 100 transmits or receivesinformation for controlling communication with the terminal apparatus200, the base station 100 uses the channel f0 (i.e., PCC), and in thecase where the base station 100 transmits live data, the base station100 uses the channel f1 (i.e., SCC) to which FTN is applied.

More specifically, in the example illustrated in FIG. 23, the basestation 100 uses, as represented by a reference numeral S551, thechannel f0 (i.e., PCC) to broadcast an SIB message to each terminalapparatus 200 positioned in the cell 10. At this time, the base station100 includes an FTN parameter in the SIB message to notify each terminalapparatus 200 positioned in the cell 10 of the FTN parameter.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S557, the channel f1 (i.e., SCC) to transmit thetransmission signal onto the PDSCH resource designated for the terminalapparatus 200.

As described above, the notification of an FTN parameter is issuedconcentratedly through a predetermined frequency channel, thereby makingit possible to decrease the overhead in a communication sequence thatuses another frequency channel. Note that choices of the frequencychannel used for the notification of an FTN parameter include a PCC andan SCC, but it is more desirable to employ the configuration in which aPCC is used to perform the procedure for the notification of an FTNparameter from the perspective that all the terminal apparatuses 200 ina cell are capable of the reception. In addition, as described above,applying a larger value than another CC (SCC) or 1 (τ=1) as thecompression coefficient corresponding to a PCC makes it possible to makethe procedure for the notification of an FTN parameter, or the like morestable.

With reference to FIGS. 22 and 23, the above describes an example of thecase where the base station 100 uses a frequency channel to which FTN isapplied to notify the terminal apparatus 200 of an FTN parameter. Notethat, although the above focuses on an example of the case where FTN isapplied to a downlink for description, it goes without saying that thesame applies to the case where FTN is applied to an uplink.

(c-3) Example of Case where FTN is not Applied to Physical ControlChannel

Next, with reference to FIGS. 24 and 25, an example of the case whereFTN is not applied to a physical control channel, but FTN is appliedwhen the notification of an FTN parameter is issued and data istransmitted will be described. FIGS. 24 and 25 are explanatory diagramseach for describing an example of a communication sequence in the casewhere FTN is employed for the downlink in the communication system inwhich carrier aggregation is employed. Note that FIGS. 24 and 25 eachillustrate an example of a communication sequence between the basestation 100 and the terminal apparatus 200 in the case where FTN is notapplied to a physical control channel, but FTN is applied when thenotification of an FTN parameter is issued and data is transmitted.

For example, similarly to the example described with reference to FIG.15, FIG. 24 illustrates an example of the case where FTN is employed fora downlink, and the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter. Note that thecommunication sequences represented by reference numerals S601 to S613in FIG. 24 are similar to the communication sequences represented byreference numerals S201 to S213 in FIG. 15, so that detailed descriptionwill be omitted.

FIG. 24 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC). In the example illustrated inFIG. 24, the base station 100 uses the channel f0 (i.e., PCC) totransmit and receive RRC connection reconfiguration such as a PDCCH anda PUCCH, and uses the channel f1 (i.e., SCC) to transmit and receive theother control channels (e.g., RRC connection, physical shared datachannel, and the like).

More specifically, in the example illustrated in FIG. 24, the basestation 100 uses, as represented by a reference numeral S601, thechannel f1 (i.e., SCC) to transmit an RRC connection reconfigurationmessage to the terminal apparatus 200. At this time, the base station100 notifies the terminal apparatus 200 of an FTN parameter (e.g.,compression coefficient τ_(i,p)) set for each cell (S601). In addition,the channel f1 (i.e., SCC) is also used to transmit an RRC connectionreconfiguration complete message from the terminal apparatus 200 as aresponse to the RRC connection reconfiguration message (S603).

In addition, when using a PDCCH to transmit allocation information of aPDSCH to the terminal apparatus 200, the base station 100 uses thechannel f0 (i.e., PCC) (S605).

Next, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target datato generate a transmission signal, and uses the channel f1 (i.e., SCC)to transmit the transmission signal onto a designated PDSCH resource(S609).

In addition, the terminal apparatus 200 returns an ACK or a NACK to thebase station 100 in accordance with a decoding result of the datatransmitted from the base station 100. At this time, the terminalapparatus 200 uses the channel f0 (i.e., PCC) to return an ACK or a NACKto the base station 100 (S613).

In addition, as another example, similarly to the example described withreference to FIG. 16, FIG. 25 illustrates an example of the case whereFTN is employed for a downlink, and the base station 100 uses systeminformation to notify the terminal apparatus 200 of an FTN parameter.Note that the communication sequences represented by reference numeralsS651 to S661 in FIG. 25 are similar to the communication sequencesrepresented by reference numerals S251 to S261 in FIG. 16, so thatdetailed description will be omitted.

FIG. 25 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC). In the example illustrated inFIG. 25, the base station 100 uses the channel f0 (i.e., PCC) totransmit and receive RRC connection reconfiguration such as a PDCCH anda PUCCH, and uses the channel f1 (i.e., SCC) to transmit and receive theother control channels (e.g., RRC connection, physical shared datachannel, and the like).

More specifically, in the example illustrated in FIG. 25, the basestation 100 uses, as represented by a reference numeral S651, thechannel f1 (i.e., SCC) to broadcast an SIB message to each terminalapparatus 200 positioned in the cell 10. At this time, the base station100 includes an FTN parameter in the SIB message to notify each terminalapparatus 200 positioned in the cell 10 of the FTN parameter.

In addition, when using a PDCCH to transmit allocation information of aPDSCH to the terminal apparatus 200, the base station 100 uses thechannel f0 (i.e., PCC) (S653).

Next, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target datato generate a transmission signal, and uses the channel f1 (i.e., SCC)to transmit the transmission signal onto a designated PDSCH resource(S657).

In addition, the terminal apparatus 200 returns an ACK or a NACK to thebase station 100 in accordance with a decoding result of the datatransmitted from the base station 100. At this time, the terminalapparatus 200 uses the channel f0 (i.e., PCC) to return an ACK or a NACKto the base station 100 (S661).

With reference to FIGS. 24 and 25, the above describes an example of thecase where FTN is not applied to a physical control channel, but FTN isapplied when the notification of an FTN parameter is issued and data istransmitted. Note that, although the above focuses on an example of thecase where FTN is applied to a downlink for description, it goes withoutsaying that the same applies to the case where FTN is applied to anuplink.

In a case where the compression coefficient is controlledcell-specifically, a semi-static case and a dynamic case are consideredas updating units of coefficients in the time direction. As an updatingunit of the semi-static case, updating the coefficient in units of aplurality of subframes, units of one radio frame, or units of aplurality of radio frames is considered. By updating the coefficient inunits of a plurality of subframes, units of one radio frame, or units ofa plurality of radio frames in this way, the transmission apparatus andthe reception apparatus can continue communication by continuing a timeof a degree which is setting performed once. In addition, by updatingthe coefficient in units of a plurality of subframes, units of one radioframe, or units of a plurality of radio frames in this way, an effect ofsuppressing an increase in overhead can be expected.

On the other hand, as an updating unit of the dynamic case, updating thecoefficient in units of one subframe or units of a plurality ofsubframes is considered. Alternatively, as the updating unit of thedynamic case, updating the coefficient aperiodically at each subframecan also be considered. By updating the coefficient in units of onesubframe or units of a plurality of subframes or updating thecoefficient aperiodically at each subframe, the transmission apparatuscan associate parameters flexibly in accordance with a change in a radiowave propagation environment.

(6) Example of Sequence in which Compression Coefficient is Changed forEach User (User-Specific)

As described above, in addition to controlling the compressioncoefficient cell-specifically to change the compression coefficient, thecompression coefficient may be controlled for each user (user-specific)to be changed. By controlling the compression coefficient for each userto change the compression coefficient, a transmission parameter can becontrolled to be changed while adapting or tracking a change in a radiowave propagation environment even in a case where the radio wavepropagation environment is different for each user or in a case wherethe radio wave propagation environment is temporally frequently changed.

In a case where the compression coefficient is changeduser-specifically, a physical control channel (PDCCH or PUCCH) may alsobe used as a channel for notifying the reception apparatus of parametersfrom the transmission apparatus or a channel for notifying the terminalapparatus 200 of parameters from the base station 100. The physicalcontrol channel can be said to be appropriate for control for each usersince the transmission is performed as a set for each related physicalshared channel (PDSCH or PUSCH). Further, of the physical controlchannels, using control information (DCI or UCI) can be said to beappropriate for notification. The control information is used to notifyof information related to user-specific scheduling such as resourceallocation, modulation encoding information, precoding information, orretransmission control information, it is appropriate to also includeall the parameters related to user-specific FTN.

In particular, in a case where a cellular system is considered, the basestation 100 preferably notifies the terminal apparatus 200 of theparameters on both uplink and downlink. This is because, in the case ofa cellular system, the base station 100 can perform control such asscheduling on the subordinate terminal apparatus 200 and the basestation 100 can also perform control related to FTN to unitarilyintegrate a flow of the control.

FIG. 26 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for the downlinkas in FIG. 16. An example of a case where the base station 100 notifiesthe terminal apparatus 200 of FTN parameters by the system informationis illustrated.

In the example illustrated in FIG. 26, the base station 100 notifies theterminal apparatus 200 of the parameters related to FTN used by the basestation 100 at the time of transmission of PDCCH in step S253 andtransmits the physical shared data channel to the terminal apparatus 200by applying the parameters that are notified of in step S257.

FIG. 27 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for the uplink.An example of a case where the base station 100 notifies the terminalapparatus 200 of the FTN parameters by the system information isillustrated.

In the example illustrated in FIG. 27, the base station 100 notifies theterminal apparatus 200 of the parameters related to FTN used by the basestation 100 at the time of transmission of PDCCH in step S253 and theterminal apparatus 200 transmits the physical shared data channel to thebase station 100 by applying the parameters that are notified of in stepS2717. The base station 100 performs various kinds of demodulation anddecoding processing including the FTN de-mapping processing based on theFTN parameter set for each cell on a reception signal to extract thedata transmitted from the terminal apparatus 200 (S273). In a case wherethe base station 100 has succeeded in decoding the data with no errorson the basis of error detection such as CRC, the base station 100 mayreturn an ACK to the terminal apparatus 200. In addition, in the casewhere the base station 100 has detected an error on the basis of errordetection such as CRC, the base station 100 may return a NACK to theterminal apparatus 200 (S275).

In a case where the transmission apparatus notifies the receptionapparatus of the parameters related to the compression coefficient as apart of the control information, it is preferable to discretely quantizethe values of the parameters from the perspective of reduction ofoverhead. Therefore, in the notification, it is preferable to notify ofthe quantized values as indexes rather than including the values of theparameters and associate the indexes with the values in a one-to-onemanner in advance. Table 2 shows an example of the association betweenindexes of the compression coefficient and the values of the compressioncoefficient.

TABLE 2 Example of Association between Index of Compression Coefficientand Value of Compression Coefficient Index of FTN Compression Value ofFTN Compression Coefficient Coefficient 0 τ0 1 τ1 2 τ2 . . . . . .

Herein, although not shown in Table 2, a region for reservation may besecured so that an association relation has extendibility. When theregion for reservation is secured, a place in which the value of theindex is large may be set as the region for reservation. In addition,the compression coefficient is a nonnegative real number. The value ofthe coefficient preferably decreases as the index increases. This isbecause a signal processing load for receiving a compressed signalincreases as the value decreases, and thus only an apparatus with a highsignal processing capability can deal with the signal processing load ina case where the reserved region is used as an actual value due tofuture extendibility. In addition, when the index is 0 in Table 2, thecompression coefficient may be set to 1 (no compression).

(7) Control (Synchronization) at Boundary of Resource Unit in TimeDirection in Case where FTN is Introduced into Communication SystemIncluding Carrier Aggregation

In a case where FTN is introduced into a communication system usingcarrier aggregation, a case where the length of the subframe differsbetween a plurality of component carriers (frequency channels) dependingon the value of the compression coefficient is considered. In a casewhere the length of the subframe differs between the plurality ofcomponent carriers, the boundaries of the resource units in the timedirection are considered to be fitted between the component carriers.This is because there is an influence on information notification andcontrol in which the component carriers are straddled, such ascross-carrier scheduling in accordance with whether the boundaries arefitted.

As a method of fitting the resource units in the time direction, amethod of fitting the boundaries of the subframes and a method offitting the boundaries of the radio frames are considered. In a casewhere the boundaries of the subframe are fitted, a case where theboundaries of the radio frames are fitted naturally can also beconsidered.

Two examples in which the boundaries of the subframes are fitted will bedescribed. FIG. 28 is an explanatory diagram for describing an exampleof synchronization of boundaries in the subframe unit at the time of thecarrier aggregation. FIG. 28 illustrates an example of a case where theboundaries in the subframe unit are aligned between the componentcarriers and the boundaries of the radio frames are also aligned.

In the example illustrated in FIG. 28, two component carriers areassumed, subframe lengths of the two component carriers are set to TSF0and TSF1, and radio frame lengths of the two component carriers are setto TRF0 and TRF1. The alignment of the boundaries of the subframesbetween the component carriers is synonymous with an operation of thesubframe lengths as TSF0==TSF1. In addition, in FIG. 28, the radio framelengths TRF0==TRF1 are set. That is, the number N of subframes per radioframe can be said to be the same between the component carriers. Thecompression coefficient t may be set to differ or to be the same betweenthe component carriers. In this case, in a case where the compressioncoefficient differs between the component carriers, a transmission timeinterval (TTI: transmission time) differs.

FIG. 29 is an explanatory diagram for describing an example ofsynchronization of boundaries in the subframe unit at the time of thecarrier aggregation. FIG. 29 illustrates an example of another casewhere the boundaries in the subframe unit are aligned between thecomponent carriers and the boundaries of the radio frames differ betweenthe component carriers.

In the example illustrated in FIG. 29, two component carriers areassumed, subframe lengths of the two component carriers are set to TSF0and TSF1, and radio frame lengths of the two component carriers are setto TRF0 and TRF1. In the example illustrated in FIG. 29, the alignmentof the boundaries of the subframes between the component carriers isalso synonymous with TSF0==TSF1. In the example illustrated in FIG. 29,however, the radio frame lengths TRF0≠TRF1 are set, that is, theboundaries of the radio frame lengths are not fitted. This means thatthe number of subframes per radio frame has a relation of M≠N. Thenumber of subframes is changed so that a ratio of a synchronizationsignal (a primary synchronization signal (PSS), a secondarysynchronization signal (SSS), or the like) or a physical broadcastchannel (PBCH) of the subframe in the radio frame is considered to belowered, that is, a ratio of a physical shared data channel (PDSCH,PUSCH, or the like) is considered to be raised, to improve frame useefficiency. As a result, the boundaries of the radio frames may not befitted between the component carriers.

In a case where the boundaries of the subframes are aligned between thecomponent carriers as in the examples illustrated in FIGS. 28 and 29,the transmission apparatus can perform control by the above-describedcross-carrier scheduling. That is, the transmission apparatus can notifyof scheduling information (DCI or the like) of another component carrierthrough a physical control channel of any component carrier.

Next, an example of a case where the boundaries of the radio frames arealigned between the component carriers will be described. FIG. 30 is adiagram illustrating an example of a case where boundaries of radioframes are aligned to be synchronized between different componentcarriers.

In the example illustrated in FIG. 30, the radio frame lengths ofcomponent carriers 0 and 1 maintain a relation of TRF0==TRF1. In theexample illustrated in FIG. 30, however, the subframe lengths TRF0≠TRF1are considered to be set in the subframe lengths of component carriers 0and 1. This can be said to be a condition occurring due to a differencein symbol disposition by the compression coefficient of FTN.

In the situation illustrated in FIG. 30, since the boundaries of thesubframes can be said not to be aligned between the component carriers,it can be said that it is preferable to avoid performing thecross-carrier scheduling under the case of this condition. That is, inthis case, it is necessary to establish a procedure between the basestation 100 and the terminal apparatus 200 when each component carriernotifies of scheduling information (DCI or the like) regarding the radioresources of the component carrier.

An example of determination of whether to perform the cross-carrierscheduling while considering synchronization of the boundaries of thesubframes and the radio frames in FTN and the carrier aggregation, asdescribed above, will be described. FIGS. 31 and 32 are flowchartsillustrating examples of determination flows for performingcross-carrier scheduling.

First, an example of a determination flow for performing thecross-carrier scheduling will be described with reference to FIG. 31.The transmission apparatus determines whether to use a plurality ofcomponent carriers (S701). Subsequently, in a case where the pluralityof component carriers are used (Yes in S701), the transmission apparatusdetermines whether the boundaries of the subframes are synchronizedbetween the component carriers (S703). In a case where the boundaries ofthe subframes are synchronized between the component carriers (Yes inS703), the transmission apparatus determines that the cross-carrierscheduling may be performed (S705). Conversely, in a case where theplurality of component carriers are not used (No in S701) or in a casewhere the boundaries of the subframes are not synchronized between thecomponent carriers (No in S703), the transmission apparatus determinesthat the cross-carrier scheduling is not performed (S707).

That is, when the boundaries of the subframes are synchronized betweenthe component carriers in the case where the plurality of componentcarriers are used, the transmission apparatus can determine that thecross-carrier scheduling may be performed.

Next, an example of the flow of the determination for performing thecross-carrier scheduling will be described with reference to FIG. 32.FIG. 32 illustrates an example of a case of determination in addition tothe values of the parameters of FTN.

The transmission apparatus first determines whether the plurality ofcomponent carriers are used (S711). Subsequently, in a case where theplurality of component carriers are used (Yes in S711), the transmissionapparatus determines whether FTN is applied (S713). Subsequently, in acase where FTN is applied (Yes in S713), the transmission apparatusdetermines whether the value of the compression coefficient differsbetween the component carriers (S715). Subsequently, in a case where thevalue of the compression coefficient differs between the componentcarriers (Yes in S715), the transmission apparatus determines whetherthe boundaries of the subframes are synchronized between the componentcarriers (S717). In a case where the boundaries of the subframes aresynchronized between the component carriers (Yes in S717), a case whereFTN is not applied (No in S713), or a case where the value of thecompression coefficient is the same between the component carriers (Noin S715), the transmission apparatus determines that the cross-carrierscheduling may be performed (S719).

Conversely, in a case where the plurality of component carriers are notused (No in S711) or a case where the boundaries of the subframes arenot synchronized between the component carriers (No in S717), thetransmission apparatus determines that the cross-carrier scheduling isnot performed (S721).

Note that, in FIGS. 31 and 32, even in the case where it is determinedthat the cross-carrier scheduling may be performed, the transmissionapparatus may separately determine whether the cross-carrier schedulingis actually performed. That is, herein, the transmission apparatusdetermines that the cross-carrier scheduling may be performed, but it isoptional for the transmission apparatus to perform the cross-carrierscheduling.

(8) Introduction of Dual-Connectivity to Communication System to whichFTN is Applied

As described above, in the case where the carrier aggregation isapplied, it is better to place the restriction on the schedulingnotification method particularly in accordance with whether theboundaries of the subframes are synchronized. On the other hand, even ina case where the boundaries of the subframes are not synchronizedbetween different component carriers, the plurality of componentcarriers may be able to be used in accordance with different methods.

As an example of the method, dual-connectivity or multi-connectivity isconsidered to be performed. This is means for simultaneously dealingwith the plurality of component carriers which are not synchronizedwhile independently maintaining the component carriers (frequencychannels). In a case where the dual-connectivity is applied, eachcomponent carrier can be used with the dual-connectivity and thus abroader bandwidth can be used for communication as a whole even in thecase where the boundaries of the subframes are not synchronized, forexample, as in FIG. 30.

FIG. 33 is a flowchart illustrating an example of determination forperforming the dual-connectivity in a case where a plurality ofcomponent carriers are used. The transmission apparatus first determineswhether to use the plurality of component carriers (S731). Subsequently,in a case where the plurality of component carriers are used (Yes inS731), the transmission apparatus determines whether the boundaries ofthe subframes are synchronized between the component carriers (S733). Ina case where the boundaries of the subframes are synchronized betweenthe component carriers (Yes in S733), the transmission apparatusdetermines that the carrier aggregation may be performed (S735) andfurther determines that the cross-carrier scheduling may be performed(S737). Conversely, in a case where the plurality of component carriersare not used (No in S731) or a case where the boundaries of thesubframes are not synchronized between the component carriers (No inS733), the transmission apparatus determines that the carrieraggregation is not performed (S739) and further determines that thecross-carrier scheduling is not performed (S741).

Next, an example of determination for performing the dual-connectivityin a case where the plurality of component carriers are used will bedescribed with reference to FIG. 34. FIG. 34 is a flowchart illustratingan example of determination for performing the dual-connectivity in acase where it is determined that a value of FTN parameter is included.

The transmission apparatus first determines whether to use the pluralityof component carriers (S751). Subsequently, in a case where theplurality of component carriers are used (Yes in S751), the transmissionapparatus determines whether FTN is applied (S753). Subsequently, in acase where FTN is applied (Yes in S753), the transmission apparatusdetermines whether the value of the compression coefficient differsbetween the component carriers (S755). In a case where the value of thecompression coefficient differs between the component carriers (Yes inS755), the transmission apparatus determines whether the boundaries ofthe subframes are continuously synchronized between the componentcarriers (S757). In a case where the boundaries of the subframes aresynchronized between the component carriers (Yes in S757), a case whereFTN is not applied (No in S753), or a case where the value of thecompression coefficient is the same between the component carriers (Noin S755), the transmission apparatus determines that the carrieraggregation may be performed (S761) and further determines that thecross-carrier scheduling may be performed (S763).

Conversely, in a case where the plurality of component carriers are notused (No in S751) or a case where the boundaries of the subframes arenot synchronized between the component carriers (No in S757), thetransmission apparatus determines that the carrier aggregation is notperformed (S765) and further determines that the cross-carrierscheduling is not performed (S767).

Note that, in FIGS. 33 and 34, even in the case where it is determinedthat the cross-carrier scheduling may be performed, the transmissionapparatus may separately determine whether the cross-carrier schedulingis actually performed. That is, herein, the transmission apparatusdetermines that the cross-carrier scheduling may be performed, but it isoptional that the transmission apparatus performs the cross-carrierscheduling.

In addition, in FIGS. 33 and 34, even in the case where it is determinedthat the carrier aggregation may be performed, the transmissionapparatus may separately determine whether the carrier aggregation isactually performed. For example, when the reception apparatus does notcorrespond to the carrier aggregation, the transmission apparatus maydetermine that the carrier aggregation is not performed even in the casewhere the transmission apparatus determines that the carrier aggregationmay be performed. In addition, the compression coefficient of the symbolinterval may differ or may be the same between different cells ordifferent component carriers.

(9) FTN Control Example Based on Another Perspective Except forFrequency Channel

Next, an example of FTN control based on another perspective except fora frequency channel will be described. As described above, theimprovement of frequency use efficiency is one of the effects caused byapplying FTN. Because of such a characteristic, the effectivenessbrought about by applying FTN sometimes changes in accordance with acontrol channel of a radio resource used in a communication system.

For example, an example of the application range within which it ispossible to obtain an effect of FTN by applying FTN includes a channel(i.e., PDSCH or PUSCH). By applying FTN to a shared channel fortransmitting and receiving live data, for example, it is possible toobtain the effect of improving frequency use efficiency and throughput.

Further, in addition to a shared channel, the application of FTN to amulticast channel is included. The multicast channel is a channel and aresource used when a broadcasting data service is provided in a cellularsystem like a multimedia broadcast multicast service (MBMS) or the like.Applying FTN to a multicast channel makes it possible, for example, toexpect the improvement of the quality of the broadcasting data service.Note that the shared channel or the multicast channel corresponds to anexample of a “second control channel.”

Meanwhile, it is desirable in some cases to refrain from applying FTN toa channel used chiefly for a control system (e.g., notification ofinformation, feedback, or the like). Information of the control systemis fundamental in the establishment of communication, so that it isthought to be important to improve the reliability of transmission andreception. Therefore, it is sometimes more preferable that inter-symbolinterference be avoided by refraining from applying FTN to a channel fortransmitting or receiving information of the control system to achievestable transmission and reception of information. In addition, even inthe case where FTN is applied to a channel for transmitting or receivinginformation of the control system, it is sometimes desirable to set anFTN parameter to lessen the influence of the inter-symbol interference(e.g., a value closer to 1 is set as the compression coefficientτ_(i,p)). Note that examples of the channel of the control systeminclude a broadcast channel, a control channel, a synchronizationchannel (or a synchronization signal), and the like. Note that theabove-described channel of the control system corresponds to an exampleof a “first control channel.”

In addition, in the communication system, a reference signal forestimating fluctuations in a radio propagation path or the like issometimes transmitted besides a channel. For the purpose of maintainingthe estimation accuracy of a radio propagation path, it is sometimesmore preferable that the application of FTN to such a reference signalbe avoided or an FTN parameter be set to lessen the influence of theinter-symbol interference.

The above describes an example of FTN control based on anotherperspective except for a frequency channel.

6. Modifications

Next, a modification of an embodiment of the present disclosure will bedescribed.

<6.1. Modification 1: Example of Control of Prefix>

First, as a modification 1, an example of control of a prefix such as aCP and a pilot symbol that can function as a guard interval inaccordance with the application status of FTN such as the applicabilityof FTN or the contents of an applied FTN parameter will be described.

As described above, in FTN, regarding a signal on which FTN processinghas been performed, the signal itself contains inter-symbolinterference. Therefore, in a communication system in which FTN isemployed, even in the case where there is no delay wave in a radiopropagation path (i.e., no inter-symbol interference occurs in a radiopropagation path), measures against inter-symbol interferenceaccompanying FTN processing have to be taken in some cases. In the casewhere these are viewed from another perspective, the above-described CPcorresponds to the measures against the inter-symbol interference in aradio propagation path, so that control that adds no CP may be employedfor FTN, which contains inter-symbol interference in the first place. Inthis case, for example, in the case of the compression coefficientτ_(i,p)<1, a transmission apparatus side just has to perform control tosatisfy a CP's length N_(CP,g)=0. Such a configuration makes it possibleto further improve frequency use efficiency.

In addition, as another example, a compression coefficient may be linkedto the length of a CP. As a specific example, a transmission apparatusmay perform control such that the length N_(CP,g) of a CP decreases withdecrease in the compression coefficient τ_(i,p). Note that, at thistime, the compression coefficient τ_(i,p) does not necessarily have tobe proportional to the length N_(CP,g) of the CP. Note that, in FTN, asthe compression coefficient τ_(i,p) decreases, the influence ofinter-symbol interference increases. Therefore, as the compressioncoefficient τ_(i,p) decreases, a reception apparatus side is required totake relatively stronger measures against inter-symbol interference inaccordance with the magnitude of the influence of inter-symbolinterference accompanying the compression coefficient τ_(i,p).Accordingly, it is also possible to address the inter-symbolinterference in the radio propagation path together.

Note that the relationship between the compression coefficient τ_(i,p)and length N_(CP,g) of a CP may be managed as a control table. Forexample, Table 3 shown below demonstrates an example of a control tablein which the range of a compression coefficient and the length of a CPis associated with each other in advance. In the example shown below asTable 3, the correspondence relationship between the range of acompression coefficient and the length of a CP is managed on the basisof a compression coefficient category index. Note that the magnituderelationship between the CPs (e.g., NCP to NCP3) of the respectivecompression coefficient category indexes with respect to length shown inTable 3 is NCP0≤NCP1≤NCP2≤NCP3≤ . . .

TABLE 3 Example of Association of Range of Compression Coefficient andLength of CP Compression Coefficient Range of Compression LengthCategory Index Coefficient of CP 0 τ0 ≤ τ < τ1 NCP0 1 τ1 ≤ τ < τ2 NCP1 2τ2 ≤ τ < τ3 NCP2 3 τ3 ≤ τ < τ4 NCP3 . . . . . . . . .

In addition, as another example, a specific compression coefficient andthe length of a CP may be associated with each other, and managed as acontrol table. For example, Table 4 shown below demonstrates an exampleof a control table in which the value of a compression coefficient andthe length of a CP is associated with each other in advance. Note that,in the example shown below as Table 4, it is assumed that thecorrespondence relationship between the value of a compressioncoefficient and the length of a CP is managed on the basis of acompression coefficient category index.

TABLE 4 Example of Association of Value of Compression Coefficient andLength of CP Compression Coefficient Value of Compression LengthCategory Index Coefficient of CP 0 τ0 NCP0 1 τ1 NCP1 2 τ2 NCP2 3 τ3 NCP3. . . . . . . . .

Note that, in the above description, the description is made, chieflyfocusing on control of the length of a CP. However, the same applies toa pilot symbol.

The above describes, as a modification 1, an example of control of aprefix such as a CP and a pilot symbol in accordance with theapplication status of FTN such as the applicability of FTN or thecontents of an applied FTN parameter.

<6.2. Modification 2: Example of Control According to Moving Speed ofApparatus>

Next, as a modification 2, an example of the case where a compressioncoefficient is controlled in accordance with the moving speed of atransmission apparatus or a reception apparatus will be described.

In the case where the moving speed of an apparatus (transmissionapparatus or reception apparatus) is high, fluctuations in a radio wavepath with respect to time also increase. Accordingly, it is anticipatedthat reception processing becomes complicated. Therefore, a transmissionapparatus side may control the value of a compression coefficient inaccordance with the moving speed of the transmission apparatus or thereception apparatus to adaptively control the load of processing on thecorresponding reception apparatus side. More specifically, thetransmission apparatus just has to perform control such that the valueof the compression coefficient increases (i.e., the compressioncoefficient has a value close to 1) with increase in the moving speed ofthe transmission apparatus or the reception apparatus. Such controlmakes it possible to perform control such that the influence of theinter-symbol interference contained in FTN itself decreases withincrease in the moving speed of the transmission apparatus or thereception apparatus.

Note that the relationship between the moving speed of an apparatus(transmission apparatus or reception apparatus) and the value of acompression coefficient may be managed as a control table. For example,Table 5 shown below demonstrates an example of a control table in whichthe moving speed of an apparatus and the length of a CP are associatedwith each other in advance. In the example shown below as Table 5, acategory referred to as mobility category is defined, and thecorrespondence relationship between the range of a compressioncoefficient and the length of a CP is associated with the mobilitycategory. Note that the magnitude relationship between the compressioncoefficients (e.g., τmobility0 to τmobility3) of the respective mobilitycategory indexes shown as Table 5 isτmobility0≤τmobility1≤τmobility2≤τmobility3≤ . . . ≤1.

TABLE 5 Example of Association of Moving Speed of Apparatus and Value ofCompression Coefficient Mobility Range of Moving Speed CompressionCategory Index (e.g., km/h) Coefficient 0 v0 ≤ v < v1 τmobility0 1 v1 ≤v < v2 τmobility1 2 v2 ≤ v < v3 τmobility2 3 v3 ≤ v < v4 τmobility3 . .. . . . . . .

The above describes, as a modification 2, an example of the case where acompression coefficient is controlled in accordance with the movingspeed of a transmission apparatus or a reception apparatus.

<6.3. Modification 3: Extension to Multi-Carrier Modulation>

The applications of the embodiment to single carrier modulation havebeen described with reference to FIGS. 7 to 10. On the other hand, theembodiment can also be applied to a multi-carrier modulation schemetypified by OFDM or orthogonal frequency-division multiple access(OFDMA).

FIGS. 35 and 36 are explanatory diagrams for describing an example of aconfiguration of a transmission apparatus according to an embodiment inwhich multi-carrier modulation is set as a base. Note that the sameconfiguration as the configuration of the transmission apparatusillustrated in FIGS. 7 and 8 is installed at the front stage of FIG. 35.In a case where the multi-carrier modulation is set as the base, it ispreferable to perform compression of the symbol disposition in the timedirection, an over-sample, the pulse shape filter for each subcarrier.In addition, the same value of the compression coefficient is preferablyaligned in a unit in a predetermined frequency direction (for example, amass of subcarriers such as a resource block of LTE). Further, the samevalue of the compression coefficient is preferably aligned betweenresource blocks simultaneously allocated to the same user terminalapparatus.

<6.4. Modification 4: Introduction of Compression in Time Direction andCompression in Frequency Direction>

(1) Overview of Compression in Frequency Direction

The technology for compressing the symbol disposition in the timedirection has been described above using the single carrier modulationas a base. On the other hand, when the multi-carrier modulation is setas a base, compression of sub-carrier disposition in a frequencydirection can also be introduced in a form of addition to thecompression of the symbol disposition in the time direction.

FIG. 37 is an explanatory diagram for describing sub-carrier disposition(conventional sub-carrier disposition) in a case where compression in afrequency direction is not performed. In addition, FIG. 38 is anexplanatory diagram for describing sub-carrier disposition in a casewhere compression in the frequency direction is performed. In theconventional disposition illustrated in FIG. 37, there arecharacteristics in which different subcarriers are disposed to beaccurately orthogonal to each other (an amplitude of an adjacentsubcarrier is 0 at a frequency at which the amplitude of a certainsubcarrier is peak). In a case where there is no compression in thefrequency direction, an interval (subcarrier spacing) betweensubcarriers has the same relation as an inverse of a symbol length(symbol period). Herein, the “symbol length” is different from a “symboldisposition interval after the compression in the time direction.”

Conversely, as illustrated in FIG. 38, in the case of the compression inthe frequency direction, a result of a relation of the subcarrierinterval # the inverse of the symbol length is obtained. That is, at thefrequency at which the amplitude of a certain subcarrier is peak, asituation in which the amplitude of an adjacent subcarrier is not 0occurs. In particular, in a case where an improvement in frequency useefficiency is considered, it is preferable to set a relation of thesubcarrier interval<the inverse of the symbol length. The exampleillustrated in FIG. 38 is based on the relation of the subcarrierinterval<the inverse of the symbol length. In the case of thecompression in the frequency direction, orthogonality of the subcarriersis collapsed and the subcarriers consequently interfere in each other.

When the compression in the frequency direction is introduced in thecommunication system, the degree of compression is preferably set as aparameter as in the compression in the time direction. In the exampleillustrated in FIG. 38, a parameter ϕ is introduced as a compressioncoefficient in the frequency direction. The parameter ϕ is used toexpress a subcarrier interval after the compression. When Δf is thesubcarrier interval and T is the symbol length and the compression inthe frequency direction is introduced, a relation of Δf=ϕ(1/T)<=1/T issatisfied.

In the foregoing description, the embodiments in which the fixedintroduction to the component carriers with regard to the introductionof the compression in the time direction, the cell-specific control, theuser-specific control, the semi-static control, the dynamic control, thenotification with the RRC signaling, the notification with the systeminformation, the notification with the physical control channel, thecontrol in accordance with the frequency of the component carrier, thecontrol by the relation of PCell/SCell, and the combination of thecarrier aggregation and the dual-connectivity have been described.

Herein, it is preferable to also fit the newly introduced compressioncoefficient in the frequency direction to the fixed introduction to thecomponent carriers, the cell-specific control, the user-specificcontrol, the semi-static control, the dynamic control, the notificationwith the RRC signaling, the notification with the system information,the notification with the physical control channel, the control inaccordance with the frequency of the component carrier, the control bythe relation of PCell/SCell, and the combination of the carrieraggregation and the dual-connectivity, as in the introduction of thecompression in the time direction.

Further, the compression in the time direction and the compression inthe frequency direction may be independently controlled, set, ornotified of. That is, values of the parameters τ and ϕ can be said to beintroduced with any relation to the communication system. Thus, it ispossible to control the disposition or density of the frequencyresources and the time flexibly, as described above, in accordance withthe radio wave propagation environment, frequency use efficiency desiredto be achieved, a data rate, a throughput, or the like. The followingTable 6 shows examples of combinations of values taken by thecompression coefficient in the time direction and the compressioncoefficient in the frequency direction.

TABLE 6 Examples of Combinations of Values Taken by CompressionCoefficient in Time Direction and Compression Coefficient in FrequencyDirection Value of τ Value of ϕ Case 1 ==1 ==1 Case 2 <1 ==1 Case 3 ==1<1 Case 4 <1 <1

That is, the transmission apparatus has a first mode in which control isperformed such that transmission is performed by narrowing a symbolinterval, a second mode in which control is performed such thattransmission is performed without narrowing a symbol interval, a thirdmode in which control is performed such that transmission is performedby narrowing a subcarrier interval, and a fourth mode in which controlis performed such that transmission is performed without narrowing asubcarrier interval. One of the first mode and the second mode isselected and one of the third mode and the fourth mode is similarlyselected.

Then, in a case where compression in the frequency direction isperformed, information regarding the compression coefficient ϕ in thefrequency direction is preferably shared between the transmissionapparatus and the reception apparatus as in the case of the compressioncoefficient t in the time direction.

For example, FIGS. 15, 20, 22, and 24 illustrate the examples of thecases in which the base station 100 notifies the terminal apparatus 200of the compression coefficient t in the time direction as the FTNparameter by the RRC connection reconfiguration as an example of thecommunication sequence in the case where FTN is employed for thedownlink. Here, the base station 100 may notify the terminal apparatus200 of the FTN parameter in substitution with the compressioncoefficient t in the time direction or notify of the compressioncoefficient ϕ in the frequency direction along with the compressioncoefficient t in the time direction.

In addition, for example, FIGS. 16, 21, 23, and 25 illustrate theexamples of the cases in which the base station 100 notifies theterminal apparatus 200 of the compression coefficient t in the timedirection as the FTN parameter by SIB as an example of the communicationsequence in the case where FTN is employed for the downlink. Here, thebase station 100 may notify the terminal apparatus 200 of the FTNparameter in substitution with the compression coefficient τ in the timedirection or notifies of the compression coefficient ϕ in the frequencydirection along with the compression coefficient t in the timedirection.

In addition, for example, FIG. 17 illustrates the example of the casewhere the base station 100 notifies the terminal apparatus 200 of thecompression coefficient t in the time direction as the FTN parameter bythe RRC connection reconfiguration as an example of the communicationsequence in the case where FTN is employed for the uplink. Here, thebase station 100 may notify the terminal apparatus 200 of the FTNparameter in substitution with the compression coefficient t in the timedirection or notify of the compression coefficient ϕ in the frequencydirection along with the compression coefficient τ in the timedirection.

In addition, for example, FIG. 18 illustrates the example of the casewhere the base station 100 notifies the terminal apparatus 200 of thecompression coefficient τ in the time direction as the FTN parameter bySIB as an example of the communication sequence in the case where FTN isemployed for the uplink. Here, the base station 100 may notify theterminal apparatus 200 of the FTN parameter in substitution with thecompression coefficient τ in the time direction or notify of thecompression coefficient ϕ in the frequency direction along with thecompression coefficient τ in the time direction.

(2) Definition of Resources in Case where Compression in Time Directionor Frequency Direction is Performed

In the embodiment, in a case where compression of the symbol interval inthe time direction or compression of the subcarrier in the frequencydirection is performed, it is preferable to give a definition inaccordance with compression or non-compression with regard to definitionof the format of radio resources. Thus, it is possible to share rules ofthe resources between the transmission apparatus and the receptionapparatus even when granularity of the resources is changed by thecompression.

(A) Definition of Resources in Compression in Time Direction

In the compression of the symbol interval in the time direction, it ispreferable to consider the length of the subframe, the number of symbolsper subframe, the length of TTI, the number of symbols per TTI, and thelike when the symbol interval in a certain communication system or acell is changed. When the length of the subframe, the number of symbolsper subframe, the length of TTI, the number of symbols per TTI, and thelike are considered, the following two cases are exemplified asembodiments.

(A-1) Case where Length of Subframe or Length of TTI is ConstantRegardless of Compression in Time Direction

FIG. 39 is an explanatory diagram for describing an example of a casewhere the length of a subframe or the length of TTI is constantregardless of compression in a time direction. FIG. 39 illustrates acase where there is no compression in the time direction (τ==1.0) and acase where there is compression in the time direction (τ′<1.0). In FIG.39, the length of a symbol block is drawn differently between the casewhere there is the compression in the time direction and the case wherethere is no compression in the time direction, which means that theinterval of the symbol disposition is different and does not mean thatthe length of the symbol length is different. In the case of the exampleillustrated in FIG. 39, the subframe length and TTI are assumed to bethe same. In the example illustrated in FIG. 39, the number of symbolsper subframe (or the number of symbols per TTI) is different dependingon whether there is the compression in the time direction (or differentcompression coefficients). A relation between the number N of symbols inthe case where there is no compression in the time direction and thenumber N′ of symbols in the case where there is the compression in thetime direction is N≠N′. In particular, when a magnitude of thecompression coefficient is t′<t, it is preferable to set the relationbetween the numbers of symbols to N′>N. Further, it is preferable toalso satisfy N′<=(τ′<τ)*N.

FIG. 40 is an explanatory diagram for describing an example of the casewhere the length of a subframe or the length of TTI is constantregardless of compression in the time direction. The example illustratedin FIG. 40 is a case where the subframe length and TTI are allowed to bedifferent. In FIG. 40, in the case where there is no compression in thetime direction, the subframe length==TTI is set. In a case where thereis the compression in the time direction, the subframe length>TTI isset. Setting of the subframe length<TTI is not allowed for the purposeof avoiding interference between the subframes. In the case of theexample illustrated in FIG. 40, a final subframe length is the same inthe compression coefficient by providing a non-transmission sectionexcept for TTI in the subframe. Note that, in FIG. 40, the length of thesymbol block is also drawn differently between the case where there isthe compression in the time direction and the case where there is nocompression in the time direction, which means that the interval of thesymbol disposition is different and does not mean that the length of thesymbol length is different.

TTI shortening (shortening TTI or shortening a transmission time) isconsidered as the technology for shortening delay of a transmission andreception time. FIG. 40 illustrates an example of a case where the TTIshortening is realized by the compression in the time direction.

In a case where the number N′ of symbols per subframe is changed inaccordance with the compression (the compression coefficient) in thetime direction, it is preferable to reconstruct the configuration of aresource element in the subframe. This is because the number of resourceelements per unit is also changed by changing the number of symbols.

FIG. 41 is a flowchart illustrating an example of a determination flowfor changing a configuration of a resource element with respect to achange in a value of a compression coefficient. Herein, as theconfiguration of the resource element, a disposition configuration of areference signal (which is a resource element or a signal which ismutually known between the transmission apparatus and the receptionapparatus, such as reference signals (RS), pilot signals, or knownsignals, and is used for channel state information (CSI) measurement,channel estimation, cell detection, cell selection, or the like) isconsidered.

The transmission apparatus first determines whether the value of thecompression coefficient is changed (S801). Subsequently, in a case whereit is determined that the value of the compression coefficient ischanged (Yes in S801), the transmission apparatus determines whether thenumber of resource elements in a predetermined resource unit is changed(S803). Subsequently, in a case where it is determined that the numberof resource elements in the predetermined resource unit is changed (Yesin S803), the transmission apparatus changes disposition spots (thefrequency and the time) of the reference signal in the resource elementdisposition (S805). Conversely, in a case where it is determined thatthe value of the compression coefficient is not changed (No in S801) ora case where it is determined that the number of resource elements inthe predetermined resource unit is not change (No in S803),subsequently, the transmission apparatus maintains the disposition spots(the frequency and the time) of the reference signal in the resourceelement disposition (S807).

As an index of the disposition, the density of RS resource elements inthe subframe (or a ratio of the RS resource elements occupied in thesubframe) is considered. The density (or the ratio) is considered to bereconfigured so that the density is constant regardless of thecompression in the time direction or to be reconfigured so that thedensity is changed by the compression in the time direction. In the casewhere the density of RS is reconfigured so that the density is constant,an effect of maintaining precision of CSI measurement or channelestimation as accurately as possible before and after the compression inthe different time direction can be expected. On the other hand, in thecase where the resource elements are reconfigured so that the density ofRS is changed, an effect of increasing or decreasing effective frequencyuse efficiency, a data rate, a throughput, or the like by thecompression in the time direction can be expected.

(A-2) Case where Number of Symbols Per Subframe or Number of Symbols PerTTI is Constant Regardless of Compression in Time Direction

Next, an example in which the number of symbols per subframe or thenumber of symbols per TTI is constant regardless of the compression inthe time direction will be described. FIG. 42 is an explanatory diagramfor describing an example in which the number of symbols per subframe orthe number of symbols per TTI is constant regardless of the compressionin the time direction. FIG. 42 illustrates an example in which thenumber of subframes per radio frame is constant (that is, the subframelength is constant) and TTI is changed in accordance with thecompression in the time direction. In this case, by providing a radiotransmission section in the subframe, it is possible to set the subframelength to be constant. Even in FIG. 42, the length of the symbol blockis drawn differently between the case where there is the compression inthe time direction and the case where there is no compression in thetime direction, which means that the interval of the symbol dispositionis different and does not mean that the length of the symbol length isdifferent. In this case, in a case where a magnitude relation of thecompression coefficient is t′<=t, a magnitude relation of TTI isTTI′<=TTI. Even in this case, this example can be said to be an exampleof the TTI shortening by the compression in the time direction.

FIG. 43 is an explanatory diagram for describing an example in which thenumber of symbols per subframe or the number of symbols per TTI isconstant regardless of the length of the subframe and the compression inthe time direction. The example illustrated in FIG. 43 is an example inwhich the number of subframes per radio frame is also changed inaccordance with the compression in the time direction. Even in FIG. 43,the length of the symbol block is drawn differently between the casewhere there is the compression in the time direction and the case wherethere is no compression in the time direction, which means that theinterval of the symbol disposition is different and does not mean thatthe length of the symbol length is different. In the case where amagnitude relation of the compression coefficient is t′<=t, a magnituderelation of the number of subframes per radio frame is M′>=M and amagnitude of TTI is TTI′<=TTI. Even in this case, this example can besaid to be an example of the TTI shortening by the compression in thetime direction.

In the case where the number of symbols per subframe is constantregardless of the compression in the time direction, it is preferable tomaintain the disposition configuration of the resource elements to bethe same. This is because by maintaining the disposition configurationof the resource elements to be the same, it is not necessary to increasethe number of disposition patterns of the RS resource elements betweenthe transmission apparatus and the reception apparatus and it ispossible to simplify mounting or the like of a memory.

(B) Definition of Resources in Compression in Frequency Direction

The relation of the radio frames, the number of symbols in accordancewith the compression in the time direction, the number of subframes, thesubframe length, and TTI have been described above, but the same pointof view of the setting is considered in the frequency direction. Forcompression of the subcarrier interval in the frequency direction in acertain communication system or a cell, setting of, for example, abandwidth of a resource block, the number of subcarriers per resourceblock, a bandwidth of the component carrier, the number of resourceblocks per component carrier, the number of subcarriers per componentcarrier, a processing size of time-frequency conversion such as IFFT,IDFT, FFT, DFT, or the like is considered.

(B-1) Case where Bandwidth of Resource Block (RB) is Constant Regardlessof Compression in Frequency Direction

FIG. 44 is an explanatory diagram for describing an example of a casewhere a bandwidth of a resource block is maintained constantlyregardless of presence or absence (magnitude) of compression in thefrequency direction. The upper part of FIG. 44 is example of a casewhere there is no compression in the frequency direction (ϕ==1.0) andthe lower part is an example of a case where there is compression in thefrequency direction (ϕ′<=ϕ<=1.0). Note that, in the example illustratedin FIG. 44, the bandwidth of the component carrier is assumed to beconstant. That is, the fact that the bandwidth of the resource block isconstant means that the number B of resource blocks per componentcarrier is also constant. However, the number of subcarriers perresource block is changed in accordance with the compression in thefrequency direction. Herein, in a case where the compression coefficientin the frequency direction decreases (ϕ′<=ϕ in FIG. 44), the number ofsubcarriers per resource block increases (K′>=K in FIG. 44).

In a case where the bandwidth of the resource block is constantregardless of the compression in the frequency direction, thetransmission apparatus changes the disposition configuration of theresource elements in accordance with presence or absence (magnitude) ofthe compression in the frequency direction. The determination forchanging the disposition configuration is the same as the determinationflow for changing the compression coefficient in the time direction, asillustrated in FIG. 41.

(B-2) Case where Number of Subcarriers Per Resource Block is ConstantRegardless of Compression in Frequency Direction

Unlike the foregoing (B-1), maintaining the number of subcarriers perresource block to be constant can also be considered. FIG. 45 is anexplanatory diagram for describing an example of a case where the numberof subcarriers per resource block is constant regardless of thecompression in the frequency direction. The upper part of FIG. 45 is anexample of a case where there is no compression in the frequencydirection (ϕ==1.0) and the lower part is an example of a case wherethere is compression in the frequency direction (ϕ′<ϕ<=1.0). In the casewhere the number of subcarriers per resource block is constantregardless of the compression in the frequency direction, the bandwidthof the resource block is changed in accordance with the compression inthe frequency direction. In addition, the number of resource blocks percomponent carrier is also changed with the change in the bandwidth ofthe resource block in accordance with the compression in the frequencydirection. In the embodiment, in a case where the compressioncoefficient in the frequency direction decreases (ϕ′<=ϕ in FIG. 45, thenumber of resource blocks per component carrier increases (B′>=B in thedrawing). However, the number K of subcarriers per resource block isconstant regardless of the compression coefficient in the frequencydirection.

In this case, with regard to the presence or absence (magnitude) of thecompression in the frequency direction, the same dispositionconfiguration of the resource elements can be shared. Herein, as theconfiguration of the resource elements, a disposition configuration of areference signal which is a resource element or a signal which ismutually known between the transmission apparatus and the receptionapparatus, such as reference signals (RS), pilot signals, or knownsignals, and is used for channel state information (CSI) measurement,channel estimation, cell detection, cell selection, or the like) isconsidered. By using the same disposition configuration of the resourceelements and the same disposition configuration of the referencesignals, it is possible to simplify the determination of the signalgeneration.

In a case where the number of subcarriers per component carrier ischanged in accordance with the compression in the frequency direction,it is preferable to switch the size of IFFT or FFT for transmission orreception. To enable the size of IFFT or FFT to be switched, it ispreferable to share table information indicating relevance of acomponent carrier bandwidth, the compression coefficient in thefrequency direction, and an FFT size (an IFFT size or a DFT size (IDFTsize)) in advance between the transmission apparatus and the receptionapparatus (for example, the base station 100 and the terminal apparatus200). The following Table 7 shows an example of the relevant table ofthe component carrier bandwidth, the compression coefficient in thefrequency direction, and the FFT size (IFFT size).

TABLE 7 Example of Relevant Table of Component Carrier Bandwidth,Compression Coefficient in Frequency Direction, and FFT Size (IFFT Size)Component Carrier Compression Coefficient in Bandwidth FrequencyDirection FFT Size  5 MHz 1.0 N_(F5 ) 0.8 N_(F5)′ (>N_(F5)) 0.6 N_(F5)″(>N_(F5)′) 10 MHz 1.0 N_(F10) 0.8 N_(F10)′ (>N_(F10)) 0.6 N_(F10)″(>N_(F10)′) . . . . . . . . .

In a case where the compression coefficient in the frequency directionat the same component carrier bandwidth decreases, the number ofsubcarriers is changed to increase. Accordingly, it is preferable to setthe table so that the FFT size (the IFFT size, the DFT size, or the IDFTsize) increases with an increase in the number of subcarriers. Forexample, when N_(F) is assumed to be the FFT size in a case where thecompression coefficient in the frequency direction is 1 (in the exampleshown in Table 7, N_(F5) in a case where the component carrier bandwidthis 5 MHz, and N_(F10) in a case where the component carrier bandwidth is10 MHz), the FFT size takes an integer value near (1/0.8)*N_(F)==1.25N_(F) in a case where the compression coefficient in the frequencydirection is changed from 1.0 to 0.8. For example, the FFT sizepreferably takes a value such as an integer obtained by rounding up thedecimal point (ceil (1.25 N_(F))) or rounding down (floor (1.25 N_(F)))or an integer of power of 2 near an integer obtained by rounding up orrounding down the decimal point.

(3) Presence or Absence of Compression in Time Direction (SymbolInterval) at Subframe Boundary or Presence or Absence of Compression inFrequency Direction (Subcarrier Interval) at Resource Block Boundary

In a case where radio resources are shared by a plurality oftransmission and reception apparatuses (multi-users), it is consideredto allocate one or both of time resources or frequency resources to eachuser. At this time, in the system described above, a subframe (or TTI)which is a time resource or a resource block which is a frequencyresource can be considered as an allocation unit.

As such a case, in a case where the compression in the time direction orthe frequency direction is considered, preferably, the compression isnot performed in a portion corresponding to a boundary of an allocationunit to the user or overlapping between the allocation units isalleviated, for example, by causing the compression coefficient of theportion corresponding to the boundary to be greater than the compressioncoefficient in another region. That is, in terms of the time direction,the symbol interval in the subframe is compressed, but the compressionis not performed at a subframe boundary. In addition, in the frequencydirection, the subcarrier interval in the resource block is compressedand the compression is not performed at a resource block boundary.

By taking such measures, the reception apparatus can demodulate ordecode a signal of the reception apparatus without demodulating ordecoding a signal of another user when the reception apparatusdemodulates or decodes the signal, namely, which consequently leads tosimplification of reception signal processing.

FIGS. 46 to 48 are explanatory diagrams for describing examples ofresource compression at a boundary of a time resource allocation unitand a boundary of a frequency resource allocation unit. FIG. 46 is anexplanatory diagram illustrating frequency-time resource disposition.FIG. 47 is an explanatory diagram illustrating a difference incompression of the symbol interval between the subframes and in thesubframe on the time axis. FIG. 48 is an explanatory diagramillustrating a difference in compression of the subcarrier intervalbetween the resource blocks and in the resource block on the frequencyaxis.

The time resources and the frequency resources of the cellular systemare continuously disposed over time and over frequency normally asillustrated in FIG. 46. That is, the subframes and the resource blocksserving as the allocation unit are continuous. In a case where theembodiment is applied to the resources continuous over time and overfrequency, the degree of the compression of the symbol interval and thedegree of the compression of the subcarrier interval are preferablydifferent at the allocation unit boundary and in the allocation unit.

For example, in a case where the resources of the time regionillustrated in FIG. 47 are considered, a symbol interval in the subframeis Tin==τT<=T when T is assumed to be a symbol length. On the otherhand, a symbol interval of the subframe boundary is considered to beTb==T. By deciding the symbol interval in the subframe and the symbolinterval at the subframe boundary, in a case where the transmissionapparatus allocates the subframes continuous over time to differentusers, it is not necessary for each user to receive the subframe otherthan the subframe allocated to the user for interference removal, andthus it is possible to simplify reception signal processing. Note thatthe symbol interval Tb of the subframe boundary is not necessarilyTb==T. Here, to simplify a processing load of the reception signal, thereception apparatus preferably take a value in which Tin<=Tb issatisfied.

The resources of the frequency region illustrated in FIG. 48 areconsidered to be the same as the resources of the time region describedabove. Whereas the subcarrier interval in the resource block isΔfin==ϕ(1/T)<=(1/T), the subcarrier interval at the resource blockboundary is Δfb==1/T (or a relation between values of Δfin<=Δfb). Bydeciding the subcarrier interval in the resource block and thesubcarrier interval at the resource block boundary in this way, thereception apparatus can simplify the processing load of the receptionsignal as in the case of the resources of the time region.

7. Application Examples

The technology according to the present disclosure is applicable to avariety of products. For example, the base station 100 may beimplemented as any type of evolved node B (eNB) such as a macro eNB or asmall eNB. A small eNB may be an eNB that covers a smaller cell than amacro cell, such as a pico eNB, a micro eNB, or a home (femto) eNB.Alternatively, the base station 100 may be implemented as another typeof base station such as a node B or a base transceiver station (BTS).The base station 100 may include a main body (which is also referred toas base station apparatus) that controls radio communication, and one ormore remote radio heads (RRHs) disposed in a different place from thatof the main body. In addition, various types of terminals describedbelow may operate as the base station 100 by temporarily orsemi-permanently executing the base station function. Moreover, at leastsome of components of the base station 100 may be implemented in a basestation apparatus or a module for the base station apparatus.

In addition, the terminal apparatus 200 may be implemented as, forexample, a mobile terminal such as a smartphone, a tablet personalcomputer (PC), a notebook PC, a portable game terminal, aportable/dongle type mobile router or a digital camera, or an onboardterminal such as a car navigation apparatus. In addition, the terminalapparatus 200 may be implemented as a terminal (which is also referredto as machine type communication (MTC) terminal) that performsmachine-to-machine (M2M) communication. Further, at least somecomponents of the terminal apparatus 200 may be implemented in modules(e.g., integrated circuit modules each including one die) mounted onthese terminals.

7.1. Application Example Regarding Base Station First ApplicationExample

FIG. 49 is a block diagram illustrating a first example of the schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 can be connected tothe base station apparatus 820 via an RF cable.

Each of the antennas 810 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the base station apparatus 820 to transmit and receive radiosignals. The eNB 800 includes the plurality of antennas 810 asillustrated in FIG. 49. For example, the plurality of antennas 810 maybe compatible with a plurality of respective frequency bands used by theeNB 800. Note that FIG. 49 illustrates the example in which the eNB 800includes the plurality of antennas 810, but the eNB 800 may also includethe one antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a radio communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operates thevarious functions of a higher layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data insignals processed by the radio communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may bundle data from a plurality of base band processorsto generate the bundled packet, and transfer the generated bundledpacket. In addition, the controller 821 may have logical functions ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, or scheduling. In addition, thecontrol may be executed in corporation with an eNB or a core networknode in the vicinity. The memory 822 includes a RAM and a ROM, andstores a program that is executed by the controller 821, and variouskinds of control data (e.g., terminal list, transmission power data,scheduling data, and the like).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to a core network 824. The controller 821may communicate with a core network node or another eNB via the networkinterface 823. In that case, the eNB 800 may be connected to a corenetwork node or another eNB through a logical interface (e.g., S1interface or X2 interface). The network interface 823 may also be awired communication interface or a radio communication interface forradio backhaul. In the case where the network interface 823 is a radiocommunication interface, the network interface 823 may use a higherfrequency band for radio communication than a frequency band used by theradio communication interface 825.

The radio communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) or LTE-Advanced,and provides radio connection to a terminal positioned in a cell of theeNB 800 via the antenna 810. The radio communication interface 825 cantypically include a baseband (BB) processor 826, an RF circuit 827, andthe like. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, multiplexing/demultiplexingand the like, and executes various kinds of signal processing of layers(such as L1, medium access control (MAC), radio link control (RLC), anda packet data convergence protocol (PDCP)). The BB processor 826 mayhave a part or all of the above-described logical functions instead ofthe controller 821. The BB processor 826 may be a memory that stores acommunication control program, or a module that includes a processor anda related circuit configured to execute the program. Updating theprogram may allow the functions of the BB processor 826 to be changed.In addition, the above-described module may be a card or a blade that isinserted into a slot of the base station apparatus 820. Alternatively,the above-described module may also be a chip that is mounted on theabove-described card or the above-described blade. Meanwhile, the RFcircuit 827 may include a mixer, a filter, an amplifier and the like,and transmits and receives radio signals via the antenna 810.

The radio communication interface 825 includes the plurality of BBprocessors 826, as illustrated in FIG. 49. For example, the plurality ofBB processors 826 may be compatible with plurality of frequency bandsused by the eNB 800. In addition, the radio communication interface 825includes the plurality of RF circuits 827, as illustrated in FIG. 49.For example, the plurality of RF circuits 827 may be compatible withrespective antenna elements. Note that FIG. 49 illustrates the examplein which the radio communication interface 825 includes the plurality ofBB processors 826 and the plurality of RF circuits 827, but the radiocommunication interface 825 may also include the one BB processor 826 orthe one RF circuit 827.

In the eNB 800 shown in FIG. 49, one or more components (thecommunication processing unit 151 and/or the notification unit 153)included in the processing unit 150 described with reference to FIG. 4may be implemented in the radio communication interface 825.Alternatively, at least some of these components may be implemented inthe controller 821. As an example, a module that includes a part (e.g.,BB processor 826) or the whole of the radio communication interface 825and/or the controller 821 may be mounted in the eNB 800, and theabove-described one or more components may be implemented in the module.In this case, the above-described module may store a program for causingthe processor to function as the above-described one or more components(i.e., program for causing the processor to execute the operations ofthe above-described one or more components) and may execute the program.As another example, the program for causing the processor to function asthe above-described one or more components may be installed in the eNB800, and the radio communication interface 825 (e.g., BB processor 826)and/or the controller 821 may execute the program. As described above,the eNB 800, the base station apparatus 820, or the above-describedmodule may be provided as an apparatus that includes the above-describedone or more components, and the program for causing the processor tofunction as the above-described one or more components may be provided.In addition, a readable recording medium having the above-describedprogram recorded thereon may be provided.

In addition, in an eNB 800 illustrated in FIG. 49, the radiocommunication unit 120 described with reference to FIG. 4 may beimplemented in the radio communication interface 825 (e.g., RF circuit827). In addition, the antenna unit 110 may be implemented in theantenna 810. In addition, the network communication unit 130 may beimplemented in the controller 821 and/or the network interface 823. Inaddition, the storage unit 140 may be implemented in the memory 822.

Second Application Example

FIG. 50 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. The eNB 830 includes one or more antennas840, a base station apparatus 850, and an RRH 860. Each antenna 840 maybe connected to the RRH 860 via an RF cable. In addition, the basestation apparatus 850 can be connected to the RRH 860 via a high speedline such as an optical fiber cable.

Each of the antennas 840 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the RRH 860 to transmit and receive radio signals. The eNB 830includes the plurality of antennas 840 as illustrated in FIG. 50. Forexample, the plurality of antennas 840 may be compatible with aplurality of respective frequency bands used by the eNB 830. Note thatFIG. 50 illustrates the example in which the eNB 830 includes theplurality of antennas 840, but the eNB 830 may include the one antenna840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a radio communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 49.

The radio communication interface 855 supports any cellularcommunication scheme such as LTE or LTE-Advanced, and provides radiocommunication to a terminal positioned in the sector corresponding tothe RRH 860 via the RRH 860 and the antenna 840. The radio communicationinterface 855 can typically include a BB processor 856 and the like. TheBB processor 856 is similar to the BB processor 826 described withreference to FIG. 49, except that the BB processor 856 is connected tothe RF circuit 864 of the RRH 860 via the connection interface 857. Theradio communication interface 855 includes the plurality of BBprocessors 856 as illustrated in FIG. 50. For example, the plurality ofBB processors 856 may be compatible with a plurality of respectivefrequency bands used by the eNB 830. Note that FIG. 50 illustrates theexample in which the radio communication interface 855 includes theplurality of BB processors 856, but the radio communication interface855 may include the one BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (radio communication interface 855) to the RRH860. The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station apparatus 850 (radio communication interface 855) to theRRH 860.

The RRH 860 includes a connection interface 861 and a radiocommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(radio communication interface 863) to the base station apparatus 850.The connection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The radio communication interface 863 transmits and receives radiosignals via the antenna 840. The radio communication interface 863 maytypically include the RF circuit 864 and the like. The RF circuit 864may include a mixer, a filter, an amplifier and the like, and transmitsand receives radio signals via the antenna 840. The radio communicationinterface 863 includes the plurality of RF circuits 864 as illustratedin FIG. 50. For example, the plurality of RF circuits 864 may becompatible with a plurality of respective antenna elements. Note thatFIG. 50 illustrates the example in which the radio communicationinterface 863 includes the plurality of RF circuits 864, but the radiocommunication interface 863 may include the one RF circuit 864.

In the eNB 830 illustrated in FIG. 50, one or more components (thecommunication processing unit 151 and/or the notification unit 153)included in the processing unit 150 described with reference to FIG. 4may be implemented in the radio communication interface 855 and/or theradio communication interface 863. Alternatively, at least some of thesecomponents may be implemented in the controller 851. As an example, amodule that includes a part (e.g., BB processor 856) or the whole of theradio communication interface 855 and/or the controller 821 may bemounted in eNB 830, and the above-described one or more components maybe implemented in the module. In this case, the above-described modulemay store a program for causing the processor to function as theabove-described one or more components (i.e., a program for causing theprocessor to execute the operations of the above-described one or morecomponents) and may execute the program. As another example, the programfor causing the processor to function as the above-described one or morecomponents may be installed in the eNB 830, and the radio communicationinterface 855 (e.g., BB processor 856) and/or the controller 851 mayexecute the program. As described above, the eNB 830, the base stationapparatus 850, or the above-described module may be provided as anapparatus that includes the above-described one or more components, andthe program for causing the processor to function as the above-describedone or more components may be provided. In addition, a readablerecording medium having the above-described program recorded thereon maybe provided.

In addition, in the eNB 830 illustrated in FIG. 50, the radiocommunication unit 120 described, for example, with reference to FIG. 4may be implemented in the radio communication interface 863 (e.g., RFcircuit 864). In addition, the antenna unit 110 may be implemented inthe antenna 840. In addition, the network communication unit 130 may beimplemented in the controller 851 and/or the network interface 853. Inaddition, the storage unit 140 may be implemented in the memory 852.

7.2. Application Example Regarding Terminal Apparatus First ApplicationExample

FIG. 51 is a block diagram illustrating an example of the schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure can be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a radio communication interface 912,one or more antenna switches 915, one or more antennas 916, a bus 917, abattery 918, and an auxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of the application layer and another layerof the smartphone 900. The memory 902 includes a RAM and a ROM, andstores a program that is executed by the processor 901, and data. Thestorage 903 can include a storage medium such as a semiconductor memoryor a hard disk. The external connection interface 904 is an interfacefor connecting an external device such as a memory card or a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) or a complementary metal oxide semiconductor (CMOS), and generatesa captured image. The sensor 907 can include, for example, a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundinput to the smartphone 900 to sound signals. The input device 909includes, for example, a touch sensor configured to detect touch onto ascreen of the display device 910, a keypad, a keyboard, a button, aswitch or the like, and receives an operation or an information inputfrom a user. The display device 910 includes a screen such as a liquidcrystal display (LCD) or an organic light-emitting diode (OLED) display,and displays an output image of the smartphone 900. The speaker 911converts sound signals output from the smartphone 900 to sound.

The radio communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and executes radiocommunication. The radio communication interface 912 may typicallyinclude a BB processor 913, an RF circuit 914, and the like. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, multiplexing/demultiplexing and the like, andexecutes various kinds of signal processing for radio communication.Meanwhile, the RF circuit 914 may include a mixer, a filter, anamplifier and the like, and transmits and receives radio signals via theantenna 916. The radio communication interface 912 may also be a onechip module that has the BB processor 913 and the RF circuit 914integrated thereon. The radio communication interface 912 may includethe plurality of BB processors 913 and the plurality of RF circuits 914as illustrated in FIG. 51. Note that FIG. 51 illustrates the example inwhich the radio communication interface 912 includes the plurality of BBprocessors 913 and the plurality of RF circuits 914, but the radiocommunication interface 912 may also include the one BB processor 913 orthe one RF circuit 914.

Further, in addition to a cellular communication scheme, the radiocommunication interface 912 may support another type of radiocommunication scheme such as a short-distance radio communicationscheme, a near field communication scheme, or a radio local area network(LAN) scheme. In that case, the radio communication interface 912 mayinclude the BB processor 913 and the RF circuit 914 for each radiocommunication scheme.

Each of the antenna switches 915 switches a connection destination ofthe antenna 916 between a plurality of circuits (e.g., circuits fordifferent radio communication schemes) included in the radiocommunication interface 912.

Each of the antennas 916 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the radio communication interface 912 to transmit and receive radiosignals. The smartphone 900 may include the plurality of antennas 916 asillustrated in FIG. 51. Note that FIG. 51 illustrates the example inwhich the smartphone 900 includes the plurality of antennas 916, but thesmartphone 900 may include the one antenna 916.

Further, the smartphone 900 may include the antenna 916 for each radiocommunication scheme. In that case, the antenna switches 915 may beomitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the radio communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to therespective blocks of the smartphone 900 illustrated in FIG. 51 viafeeder lines that are partially illustrated as dashed lines in thefigure. The auxiliary controller 919 operates a minimum necessaryfunction of the smartphone 900, for example, in a sleep mode.

In the smartphone 900 illustrated in FIG. 51, one or more components(the information acquisition unit 241 and/or the communicationprocessing unit 243) included in the processing unit 240 described withreference to FIG. 5 may be implemented in the radio communicationinterface 912. Alternatively, at least some of these components may beimplemented in the processor 901 or the auxiliary controller 919. As anexample, a module that includes a part (e.g., BB processor 913) or thewhole of the radio communication interface 912, the processor 901 and/orthe auxiliary controller 919 may be mounted in the smartphone 900, andthe above-described one or more components may be implemented in themodule. In this case, the above-described module may store a program forcausing the processor to function as the above-described one or morecomponents (i.e., a program for causing the processor to execute theoperations of the above-described one or more components) and mayexecute the program. As another example, the program for causing theprocessor to function as the above-described one or more components maybe installed in the smartphone 900, and the radio communicationinterface 912 (e.g., BB processor 913), the processor 901 and/or theauxiliary controller 919 may execute the program. As described above,the smartphone 900 or the above-described module may be provided as anapparatus that includes the above-described one or more components, andthe program for causing the processor to function as the above-describedone or more components may be provided. In addition, a readablerecording medium having the above-described program recorded thereon maybe provided.

In addition, in the smartphone 900 illustrated in FIG. 51, the radiocommunication unit 220 described, for example, with reference to FIG. 5may be implemented in the radio communication interface 912 (e.g., RFcircuit 914). In addition, the antenna unit 210 may be implemented inthe antenna 916. In addition, the storage unit 230 may be implemented inthe memory 902.

Second Application Example

FIG. 52 is a block diagram illustrating an example of the schematicconfiguration of a car navigation apparatus 920 to which the technologyof the present disclosure can be applied. The car navigation apparatus920 includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a radio communication interface 933, one ormore antenna switches 936, one or more antennas 937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls thenavigation function and another function of the car navigation apparatus920. The memory 922 includes a RAM and a ROM, and stores a program thatis executed by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure the position (e.g., latitude, longitude, and altitude) of thecar navigation apparatus 920. The sensor 925 may include, for example, agroup of sensors such as a gyro sensor, a geomagnetic sensor, and abarometric sensor. The data interface 926 is connected to, for example,an in-vehicle network 941 via a terminal that is not illustrated, andacquires data such as vehicle speed data generated by the vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g., CD or DVD) that is inserted into the storage medium interface928. The input device 929 includes, for example, a touch sensorconfigured to detect touch onto a screen of the display device 930, abutton, a switch or the like and receives an operation or an informationinput from a user. The display device 930 includes a screen such as anLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs the sound of thenavigation function or the content that is reproduced.

The radio communication interface 933 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and executes radiocommunication. The radio communication interface 933 may typicallyinclude a BB processor 934, an RF circuit 935, and the like. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, multiplexing/demultiplexing and the like, andexecutes various kinds of signal processing for radio communication.Meanwhile, the RF circuit 935 may include a mixer, a filter, anamplifier and the like, and transmits and receives radio signals via theantenna 937. The radio communication interface 933 may also be a onechip module that has the BB processor 934 and the RF circuit 935integrated thereon. The radio communication interface 933 may includethe plurality of BB processors 934 and the plurality of RF circuits 935as illustrated in FIG. 52. Note that FIG. 52 illustrates the example inwhich the radio communication interface 933 includes the plurality of BBprocessors 934 and the plurality of RF circuits 935, but the radiocommunication interface 933 may also include the one BB processor 934 orthe one RF circuit 935.

Further, in addition to a cellular communication scheme, the radiocommunication interface 933 may support another type of radiocommunication scheme such as a short-distance radio communicationscheme, a near field communication scheme, or a radio LAN scheme. Inthat case, the radio communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each radio communicationscheme.

Each of the antenna switches 936 switches a connection destination ofthe antenna 937 between a plurality of circuits (e.g., circuits fordifferent radio communication schemes) included in the radiocommunication interface 933.

Each of the antennas 937 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the radio communication interface 933 to transmit and receive radiosignals. The car navigation apparatus 920 may include the plurality ofantennas 937 as illustrated in FIG. 52. Note that FIG. 52 illustrates anexample in which the car navigation apparatus 920 includes the pluralityof antennas 937, but the car navigation apparatus 920 may include theone antenna 937.

Further, the car navigation apparatus 920 may include the antenna 937for each radio communication scheme. In that case, the antenna switches936 may be omitted from the configuration of the car navigationapparatus 920.

The battery 938 supplies power to the respective blocks of the carnavigation apparatus 920 illustrated in FIG. 52 via feeder lines thatare partially illustrated as dashed lines in the figure. In addition,the battery 938 accumulates power supplied from the vehicle side.

In the car navigation apparatus 920 illustrated in FIG. 52, one or morecomponents (the information acquisition unit 241 and/or thecommunication processing unit 243) included in the processing unit 240described with reference to FIG. 5 may be implemented in the radiocommunication interface 933. Alternatively, at least some of thesecomponents may be implemented in the processor 921. As an example, amodule that includes a part (e.g., BB processor 934) or the whole of theradio communication interface 933 and/or the processor 921 may bemounted in the car navigation apparatus 920, and the above-described oneor more components may be implemented in the module. In this case, theabove-described module may store a program for causing the processor tofunction as the above-described one or more components (i.e., a programfor causing the processor to execute the operations of theabove-described one or more components) and may execute the program. Asanother example, the program for causing the processor to function asthe above-described one or more components may be installed in the carnavigation apparatus 920, and the radio communication interface 933(e.g., BB processor 934) and/or the processor 921 may execute theprogram. As described above, the car navigation apparatus 920 or theabove-described module may be provided as an apparatus that includes theabove-described one or more components, and the program for causing theprocessor to function as the above-described one or more components maybe provided. In addition, a readable recording medium having theabove-described program recorded thereon may be provided.

In addition, in the car navigation apparatus 920 illustrated in FIG. 52,the radio communication unit 220 described, for example, with referenceto FIG. 5 may be implemented in the radio communication interface 933(e.g., RF circuit 935). In addition, the antenna unit 210 may beimplemented in the antenna 937. In addition, the storage unit 230 may beimplemented in the memory 922.

In addition, the technology according to the present disclosure may alsobe implemented as an in-vehicle system (or a vehicle) 940 including oneor more blocks of the above-described car navigation apparatus 920, thein-vehicle network 941, and a vehicle module 942. That is, thein-vehicle system (or the vehicle) 940 may be provided as an apparatusthat includes the information acquisition unit 241 and/or thecommunication processing unit 243. The vehicle module 942 generatesvehicle-side data such as vehicle speed, engine speed, or troubleinformation, and outputs the generated data to the in-vehicle network941.

8. Conclusion

With reference to FIGS. 3 to 52, the above describes the apparatus andthe processing according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, for example, inthe case where focus is placed on the downlink of the system 1, the basestation 100 notifies the terminal apparatus 200 of a compressioncoefficient in a time direction or a frequency direction (e.g.,compression coefficient decided for each cell) decided in accordancewith a communication environment as an FTN parameter. In addition, thebase station 100 modulates a transmission target data destined for theterminal apparatus 200, and performs FTN mapping processing on themodulated bit sequence to adjust the symbol intervals or a subcarrierinterval in the bit sequence. The base station 100 then transmits atransmission signal obtained by performing digital/analog conversion,radio frequency processing, and the like on the bit sequence on whichFTN mapping processing has been performed to the terminal apparatus 200.On the basis of such a configuration, the terminal apparatus 200performs FTN de-mapping processing on the bit sequence obtained from areception signal from the base station 100 on the basis of a compressioncoefficient in the time direction or the frequency direction of whichthe terminal apparatus 200 has been notified beforehand, thereby makingit possible to decode the data transmitted from the base station 100.

In addition, as another example, in the case where focus is placed onthe uplink of the system 1, the base station 100 notifies the terminalapparatus 200 of a compression coefficient in a time direction or afrequency direction (e.g., compression coefficient decided for eachcell) decided in accordance with a communication environment as an FTNparameter. Upon receiving this notification, the terminal apparatus 200modulates transmission target data destined for the base station 100,and performs FTN mapping processing on the modulated bit sequence toadjust the symbol intervals or a subcarrier interval in the bitsequence. The terminal apparatus 200 then transmits a transmissionsignal obtained by performing digital/analog conversion, radio frequencyprocessing, and the like on the bit sequence on which FTN mappingprocessing has been performed to the base station 100. On the basis ofsuch a configuration, the base station 100 performs FTN de-mappingprocessing on the bit sequence obtained from a reception signal from theterminal apparatus 200 on the basis of a compression coefficient in thetime direction or the frequency direction of which the terminalapparatus 200 has been notified beforehand, thereby making it possibleto decode the data transmitted from the base station 100.

As described above, according to an embodiment of the presentdisclosure, the communication system according to the present embodimenttakes into consideration the load of the processing of addressinginter-symbol interference or inter-subcarrier interference in areception apparatus, and is configured to be capable of adaptivelyadjusting a compression coefficient. Such a configuration makes itpossible to balance between the load in a reception apparatus andfrequency use efficiency in a more favorable manner. That is, accordingto the present embodiment, it is possible to use and accommodate variouskinds of frequency and various apparatuses in a communication system,and further improve the extendibility and flexibility of thecommunication system.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

An apparatus including:

a communication unit configured to perform radio communication; and

a control unit configured to perform control such that transmission isperformed from the communication unit to a terminal by narrowing atleast one of a symbol interval of a complex symbol sequence in a timedirection and a subcarrier interval of the complex symbol sequence in afrequency direction, the complex symbol sequence being converted from abit sequence, the symbol interval and the subcarrier interval being seton a basis of a predetermined condition.

(2)

The apparatus according to (1),

in which the control unit sets a narrowing amount of the symbol intervalor a narrowing amount of the subcarrier interval fixedly.

(3)

The apparatus according to (1),

in which the control unit sets a narrowing amount of the symbol intervalor a narrowing amount of the subcarrier interval for each cell or eachcomponent carrier.

(4)

The apparatus according to (3),

in which the control unit sets the narrowing amount of the symbolinterval or the narrowing amount of the subcarrier interval inaccordance with information transmitted with signaling of a higherlayer.

(5)

The apparatus according to (1),

in which the control unit sets a narrowing amount of the symbol intervalor a narrowing amount of the subcarrier interval dynamically for apredetermined time.

(6)

The apparatus according to (5),

in which the control unit sets the narrowing amount of the symbolinterval or the narrowing amount of the subcarrier interval inaccordance with information transmitted with a physical control channel.

(7)

The apparatus according to any of (1) to (6),

in which the control unit operates in a first mode in which the controlis performed such that the transmission is performed from thecommunication unit to the terminal by narrowing the symbol interval anda second mode in which the control is performed such that thetransmission is performed from the communication unit to the terminalwithout narrowing the symbol interval.

(8)

The apparatus according to (7), in which the control unit uses a sametransmission time length between the first mode and the second mode.

(9)

The apparatus according to (8),

in which the control unit uses different resource element dispositionconfigurations between the first mode and the second mode.

(10)

The apparatus according to (7),

in which the control unit uses a same number of transmission symbolsbetween the first mode and the second mode.

(11)

The apparatus according to (10),

in which the control unit uses a same radio frame length between thefirst mode and the second mode.

(12)

The apparatus according to any of (1) to (12),

in which the control unit operates in a third mode in which the controlis performed such that the transmission is performed from thecommunication unit to the terminal by narrowing the subcarrier intervaland a fourth mode in which the control is performed such that thetransmission is performed from the communication unit to the terminalwithout narrowing the subcarrier interval.

(13)

The apparatus according to (12),

in which the control unit uses a same resource block bandwidth betweenthe third mode and the fourth mode.

(14)

The apparatus according to (13),

in which the control unit uses different resource element dispositionconfigurations between the third mode and the fourth mode.

(15)

The apparatus according to (12),

in which the control unit uses a same number of subcarriers per resourceblock between the third mode and the fourth mode.

(16)

The apparatus according to (15),

in which the control unit uses different numbers of resource blocks percomponent carrier between the third mode and the fourth mode.

(17)

The apparatus according to any of (1) to (16), in which the control unituses a plurality of cells or component carriers in carrier aggregation.

(18)

The apparatus according to (17),

in which the control unit causes at least one of a narrowing amount ofthe symbol interval and a narrowing amount of the subcarrier interval todiffer between the different cells or the different component carriers.

(19)

The apparatus according to (18),

in which the control unit aligns boundaries between different cells ordifferent component carriers in the time direction in a first mode inwhich the control is performed such that the transmission is performedfrom the communication unit to the terminal by narrowing the symbolinterval.

(20)

The apparatus according to (17),

in which the control unit causes at least one of a narrowing amount ofthe symbol interval and a narrowing amount of the subcarrier interval tobe same between the different cells or the different component carriers.

(21)

The apparatus according to any of 817) to (20),

in which the control unit excludes the cells or the component carriersfrom a combination of the carrier aggregation in a case where anarrowing amount differs between the cells or the component carriers andboundaries in the time direction or boundaries in the frequencydirection are not synchronized in a first mode in which the control isperformed such that the transmission is performed from the communicationunit to the terminal by narrowing the symbol interval or a third mode inwhich the control is performed such that the transmission is performedfrom the communication unit to the terminal by narrowing the subcarrierinterval.

(22)

The apparatus according to any of (1) to (21),

in which the control unit uses a plurality of cells or componentcarriers in dual-connectivity.

(23)

The apparatus according to (22),

in which the control unit causes at least one of a narrowing amount ofthe symbol interval and a narrowing amount of the subcarrier interval todiffer between the different cells or the different component carriers.

(24)

The apparatus according to 822),

in which the control unit causes at least one of a narrowing amount ofthe symbol interval and a narrowing amount of the subcarrier interval tobe same between the different cells or the different component carriers.

(25)

The apparatus according to (1),

in which the control unit causes a narrowing amount of the symbolinterval to differ between a boundary in the time direction and a regionother than the boundary in a first mode in which the control isperformed such that the transmission is performed from the communicationunit to the terminal by narrowing the symbol interval.

(26)

The apparatus according to (25),

in which the control unit does not narrow the symbol interval at theboundary in the time direction.

(27)

The apparatus according to (1),

in which the control unit causes a narrowing amount of the subcarrierinterval to differ between a boundary in the frequency direction and aregion other than the boundary in a third mode in which the control isperformed such that the transmission is performed from the communicationunit to the terminal by narrowing the subcarrier interval.

(28)

The apparatus according to (27),

in which the control unit does not narrow the subcarrier interval at theboundary in the frequency direction.

(29)

The apparatus according to any of (1) to (28),

in which, in a case where the control is performed such that thetransmission is performed from the communication unit to the terminal bynarrowing the symbol interval or the subcarrier interval, the controlunit causes a narrowing amount of the symbol interval or a narrowingamount of the subcarrier interval to differ between a boundary of atleast one of time resources or frequency resources with which a signalis transmitted to a different user and a region other than the boundary.

(30)

The apparatus according to (29),

in which the control unit does not narrow the symbol interval or thesubcarrier interval at a boundary of at least one of the time resourcesor the frequency resources with which the signal is transmitted to thedifferent user.

(31)

A method including:

performing radio communication; and

performing, by a processor, control such that radio transmission isperformed from the communication unit to a terminal by narrowing atleast one of a symbol interval of a complex symbol sequence in a timedirection and a subcarrier interval of the complex symbol sequence in afrequency direction, the complex symbol sequence being converted from abit sequence, the symbol interval and the subcarrier interval being seton a basis of a predetermined condition.

(32)

A computer program for causing a computer to execute:

performing radio communication; and

performing control such that radio transmission is performed from thecommunication unit to a terminal by narrowing at least one of a symbolinterval of a complex symbol sequence in a time direction and asubcarrier interval of the complex symbol sequence in a frequencydirection, the complex symbol sequence being converted from a bitsequence, the symbol interval and the subcarrier interval being set on abasis of a predetermined condition.

REFERENCE SIGNS LIST

-   1 system-   10 cell-   100 base station-   110 antenna unit-   120 radio communication unit-   130 network communication unit-   140 storage unit-   150 processing unit-   151 communication processing unit-   153 notification unit-   200 terminal apparatus-   210 antenna unit-   220 radio communication unit-   230 storage unit-   240 processing unit-   241 information acquisition unit-   243 communication processing unit

1. An apparatus comprising: a communication unit configured to performradio communication; and a control unit configured to perform controlsuch that transmission is performed from the communication unit to aterminal by narrowing at least one of a symbol interval of a complexsymbol sequence in a time direction and a subcarrier interval of thecomplex symbol sequence in a frequency direction, the complex symbolsequence being converted from a bit sequence, the symbol interval andthe subcarrier interval being set on a basis of a predeterminedcondition.
 2. The apparatus according to claim 1, wherein the controlunit sets a narrowing amount of the symbol interval or a narrowingamount of the subcarrier interval fixedly.
 3. The apparatus according toclaim 1, wherein the control unit sets a narrowing amount of the symbolinterval or a narrowing amount of the subcarrier interval for each cellor each component carrier in accordance with information transmittedwith signaling of a higher layer.
 4. The apparatus according to claim 1,wherein the control unit sets a narrowing amount of the symbol intervalor a narrowing amount of the subcarrier interval dynamically for apredetermined time in accordance with information transmitted with aphysical control channel.
 5. The apparatus according to claim 1, whereinthe control unit operates in a first mode in which the control isperformed such that the transmission is performed from the communicationunit to the terminal by narrowing the symbol interval and a second modein which the control is performed such that the transmission isperformed from the communication unit to the terminal without narrowingthe symbol interval.
 6. The apparatus according to claim 5, wherein thecontrol unit uses a same transmission time length between the first modeand the second mode.
 7. The apparatus according to claim 6, wherein thecontrol unit uses different resource element disposition configurationsbetween the first mode and the second mode.
 8. The apparatus accordingto claim 5, wherein the control unit uses a same number of transmissionsymbols between the first mode and the second mode.
 9. The apparatusaccording to claim 8, wherein the control unit uses a same radio framelength between the first mode and the second mode.
 10. The apparatusaccording to claim 1, wherein the control unit operates in a third modein which the control is performed such that the transmission isperformed from the communication unit to the terminal by narrowing thesubcarrier interval and a fourth mode in which the control is performedsuch that the transmission is performed from the communication unit tothe terminal without narrowing the subcarrier interval.
 11. Theapparatus according to claim 10, wherein the control unit uses a sameresource block bandwidth between the third mode and the fourth mode. 12.The apparatus according to claim 11, wherein the control unit usesdifferent resource element disposition configurations between the thirdmode and the fourth mode.
 13. The apparatus according to claim 10,wherein the control unit uses a same number of subcarriers per resourceblock between the third mode and the fourth mode.
 14. The apparatusaccording to claim 13, wherein the control unit uses different numbersof resource blocks per component carrier between the third mode and thefourth mode.
 15. The apparatus according to claim 1, wherein the controlunit uses a plurality of cells or component carriers in carrieraggregation to align boundaries between different cells or differentcomponent carriers in the time direction in a first mode in which thecontrol is performed such that the transmission is performed from thecommunication unit to the terminal by narrowing the symbol interval. 16.The apparatus according to claim 1, wherein the control unit uses aplurality of cells or component carriers in carrier aggregation toexclude the cells or the component carriers from a combination of thecarrier aggregation in a case where a narrowing amount differs betweenthe cells or the component carriers and boundaries in the time directionor boundaries in the frequency direction are not synchronized in a firstmode in which the control is performed such that the transmission isperformed from the communication unit to the terminal by narrowing thesymbol interval or a third mode in which the control is performed suchthat the transmission is performed from the communication unit to theterminal by narrowing the subcarrier interval.
 17. The apparatusaccording to claim 1, wherein the control unit uses a plurality of cellsor component carriers in dual-connectivity.
 18. The apparatus accordingto claim 1, wherein the control unit causes a narrowing amount of thesymbol interval to differ between a boundary in the time direction and aregion other than the boundary in a first mode in which the control isperformed such that the transmission is performed from the communicationunit to the terminal by narrowing the symbol interval.
 19. The apparatusaccording to claim 18, wherein the control unit does not narrow thesymbol interval at the boundary in the time direction.
 20. A methodcomprising: performing radio communication; and performing, by aprocessor, control such that radio transmission is performed from thecommunication unit to a terminal by narrowing at least one of a symbolinterval of a complex symbol sequence in a time direction and asubcarrier interval of the complex symbol sequence in a frequencydirection, the complex symbol sequence being converted from a bitsequence, the symbol interval and the subcarrier interval being set on abasis of a predetermined condition.